Illumination optical system, exposure apparatus, device production method, and light polarization unit

ABSTRACT

An illumination optical system which illuminates an illumination objective surface with a light from a light source. The illumination optical system includes a spatial light modulator which includes a plurality of optical elements arranged within a predetermined plane and controlled individually, and which forms a light intensity distribution in an illumination pupil of the illumination optical system; and a polarization unit which is arranged in a position optically conjugate with the predetermined plane, and which polarizes an incident light beam having a first and second partial light beams, coming into the polarization unit such that the first and second partial light beams have polarization states different from each other, and emits the polarized incident light beam as an outgoing light beam, wherein the polarization unit changes, in a cross section of the outgoing light beam, a ratio between a cross sectional areas of the first and second partial light beams.

This is a divisional of U.S. patent application Ser. No. 14/124,034filed Apr. 22, 2014 (now U.S. Pat. No. 9,599,905), which in turn is aU.S. national stage of International Application No. PCT/JP2011/077200filed Nov. 25, 2011 claiming the conventional priority of U.S.Provisional Patent Application No. 61/494,102, filed on Jun. 7, 2011.The disclosure of each of the prior applications is incorporated hereinby reference in its entirety.

TECHNICAL FIELD

The present teaching relates to an illumination optical system, anexposure apparatus, a device production method, and a polarization unit.

BACKGROUND ART

In a typical exposure apparatus of this type, the light, which isradiated from a light source, forms, via a fly's eye lens as an opticalintegrator, a secondary light source as a substantial surface lightsource composed of a large number of light sources (in general, apredetermined light intensity distribution on an illumination pupil). Inthe following description, the light intensity distribution, which isprovided on the illumination pupil, is referred to as “pupil intensitydistribution”. Further, the illumination pupil is defined as theposition which makes the illumination objective surface or illuminationobjective plane (mask or wafer in the case of the exposure apparatus)the Fourier transform plane of the illumination pupil by the aid of theaction of the optical system disposed between the illumination pupil andthe illumination objective surface (plane).

The light, which comes from the secondary light source, is collected bya condenser optical system, and then illuminates a mask, on which apredetermined pattern is formed, in a superimposed (overlaid) manner.The light, which is transmitted through the mask, forms an image on awafer via a projection optical system, and the mask pattern is projectedand exposed (transferred) onto the wafer. The pattern, which is formedon the mask, is fine and minute. In order to correctly transfer the finepattern onto the wafer, it is indispensable to obtain a uniformilluminance distribution on the wafer.

Conventionally, it has been suggested a technique in which an annular(circular zonal) or multi-pole-shaped secondary light source (pupilintensity distribution) is formed on an illumination pupil defined on aback focal plane of a fly's eye lens or in the vicinity thereof by theaction of an aperture diaphragm which is equipped with a wave plate (awavelength plate) and which is arranged just downstream from the fly'seye lens, and the setting is made such that the light beam (luminousflux), which passes through the secondary light source, is in a linearpolarization state in which the circumferential direction is thepolarization direction (hereinafter abbreviated and referred to as“circumferential direction (azimuthal direction) polarization state”)(see, for example, Japanese Patent Publication No. 3246615).

SUMMARY

In order to realize the illumination condition suitable to faithfullytransfer fine patterns having various forms, it is desired to improvethe degree of freedom in the change of the shape (broad conceptincluding the size) of the pupil intensity distribution and the changeof the polarization state. However, in the case of the conventionaltechnique described in Patent Document 1, it has been impossible tochange the shape of the pupil intensity distribution and thepolarization state except if the aperture diaphragm equipped with thewave plate is exchanged.

The present teaching has been made taking the foregoing problem intoconsideration, an object of which is to provide an illumination opticalsystem having a high degree of freedom in the change of the polarizationstate. Another object of the present teaching is to provide an exposureapparatus and a method for producing a device which make it possible tocorrectly transfer a fine pattern to a photosensitive substrate under anadequate illumination condition by using the illumination optical systemhaving the high degree of freedom in the change of the polarizationstate.

A first aspect of the present teaching provides an illumination opticalsystem which illuminates an illumination objective surface with a lightfrom a light source, the illumination optical system including a spatiallight modulator which includes a plurality of optical elements arrangedwithin a predetermined plane and controlled individually, and whichforms a light intensity distribution in a variable manner in anillumination pupil of the illumination optical system; and apolarization unit which is arranged in a conjugate position opticallyconjugate with the predetermined plane in an optical path of theillumination optical system, and which polarizes an incident light beamhaving a first partial light beam and a second partial light beamdifferent from the first partial light beam, coming into thepolarization unit such that the first partial light beam and the secondpartial light beam have polarization states different from each other,and emits the polarized incident light beam as an outgoing light beam,

wherein the polarization unit changes, in a cross section of theoutgoing light beam, a ratio between a cross sectional area of the firstpartial light beam and a cross sectional area of the second partiallight beam.

A second aspect of the present teaching provides an exposure apparatusincluding the illumination optical system of the first aspect forilluminating a predetermined pattern, the exposure apparatus exposing aphotosensitive substrate with the predetermined pattern.

A third aspect of the present teaching provides a device productionmethod including the steps of: exposing the photosensitive substratewith the predetermined pattern by using the exposure apparatus of thesecond aspect; developing the photosensitive substrate to which thepredetermined pattern is transferred and forming a mask layer having ashape corresponding to the predetermined pattern on a surface of thephotosensitive substrate; and processing the surface of thephotosensitive substrate via the mask layer.

A fourth aspect of the present teaching provides a polarization unitwhich changes a polarization state of a part of an incident light beamhaving a rectangular cross section and then emits the incident lightbeam as an outgoing light beam, the polarization unit including: a firstoptical element which is arranged on a first plane along the crosssection of the incident light beam and which changes a polarizationstate of a second partial light beam in the incident light beam, withoutexerting any effect on a first partial light beam in the incident lightbeam; and a second optical element which is arranged on a second planealong the cross section of the incident light beam and which changes apolarization state of a third partial light beam which is at least apart of the second partial light beam passed through the first opticalelement, and a polarization state of a fourth partial light beam whichis at least a part of the first partial light beam which coming into thesecond optical element without passing through the first opticalelement, wherein the first optical element has a first edge extending ina third direction obliquely intersecting one pair of sides of therectangular cross section of the incident light beam, and a second edgeextending in a fourth direction different from the third direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a configuration of a main part of anillumination optical system according to an embodiment of the presentteaching;

FIG. 2 schematically shows a configuration of an exposure apparatusaccording to the embodiment;

FIG. 3 is a diagram for explaining a configuration and function oreffect of a spatial light modulator;

FIG. 4 is a partial perspective view of a main part of the spatial lightmodulator;

FIG. 5 schematically shows a configuration of a polarization unitaccording to the embodiment;

FIG. 6 shows an aspect (a look) of a light beam coming into thepolarization unit of FIG. 5;

FIG. 7 shows a polarization state of the light beam at a position justdownstream of the polarization unit;

FIG. 8 shows partial areas on an arrangement plane of the spatial lightmodulator;

FIGS. 9A and 9B show eight pole-shaped pupil intensity distributions ina circumferential direction polarization states;

FIG. 10 shows an annular pupil intensity distribution in acircumferential direction polarization state;

FIG. 11 shows an eight pole-shaped pupil intensity distribution in aradial direction polarization state;

FIG. 12 is a first diagram for explaining an example of operation of acontrol system;

FIGS. 13A to 13D are second diagrams for explaining the example ofoperation of the control system;

FIG. 14 shows a four pole-shaped pupil intensity distribution in acircumferential direction polarization state;

FIG. 15 shows a nine pole-shaped pupil intensity distribution obtainedby adding a central pole to the eight pole-shaped pupil intensitydistribution in a circumferential direction polarization state;

FIG. 16 shows an example of a configuration of a polarization unitprovided with a depolarizing element insertable to and removable from anillumination optical path;

FIG. 17 shows a five pole-shaped pupil intensity distribution obtainedby adding a central pole to the four pole-shaped pupil intensitydistribution in the circumferential direction polarization state;

FIG. 18 shows an example of a configuration for controlling thecross-sectional area of each partial light beam in a mutuallyindependent manner by using a polarization unit composed of a pair ofoptical rotation members having trapezoidal outer shapes;

FIG. 19 shows a first modification of FIG. 18;

FIG. 20 shows a second modification of FIG. 18;

FIG. 21 shows an example of configuration in which it is used an opticalrotation member composed of a clockwise optical rotation member and acounterclockwise optical rotation member;

FIG. 22 shows an example of a configuration in which it is provided aphase difference imparting member on an optical Fourier transformationplane of the arrangement plane of the spatial light modulator;

FIGS. 23A to 23C show an example of forming an optical elementequivalent to an optical rotator by using a pair of wave plates;

FIG. 24 shows a specific example of arrangement of the pair of opticalrotation members constituting the polarization unit;

FIG. 25 shows an example of moving the pair of optical rotation membersarranged parallel to a plane orthogonal to the optical axis, in adirection parallel to a plane conjugate with the arrangement plane ofthe spatial light modulator;

FIG. 26 shows an example of moving the pair of optical rotation membersarranged parallel to the plane conjugate with the arrangement plane ofthe spatial light modulator, in a direction parallel to the conjugateplane;

FIG. 27 shows a modification in which it is used a pair of wave platesto constitute a polarization unit;

FIG. 28 shows another modification in which it is used a pair of waveplates to constitute a polarization unit;

FIG. 29 shows a modification in which the polarization unit is arrangedin a conjugate position in an optical path on the light source side ofthe spatial light modulator;

FIG. 30 shows a modification in which the polarization unit is arrangedon the optical Fourier transformation plane of the arrangement plane ofthe spatial light modulator, to transform a linearly polarized incidentlight into a circumferential direction linearly polarized light or aradial direction linearly polarized light;

FIG. 31 schematically shows a configuration of the polarization unit inFIG. 30 which transforms the linearly polarized incident light into thecircumferential direction linearly polarized light or the radialdirection linearly polarized light;

FIG. 32 shows a modification in which the polarization units is arrangedboth in a conjugate position in an optical path on the illuminationobjective plane side of the spatial light modulator, and in a conjugateposition in an optical path on the light source side of the spatiallight modulator;

FIGS. 33A and 33B schematically show modifications in which polarizationunits are composed of three optical rotation members, respectively;

FIG. 34 schematically shows a modification in which the polarizationunit is composed of four optical rotation members;

FIG. 35 schematically shows a modification in which it is provided aphase modulation member to reduce elliptical polarization of light ofoblique polarization;

FIG. 36 is a flowchart showing steps of producing a semiconductordevice; and

FIG. 37 is a flowchart showing steps of producing a liquid crystaldevice such as a liquid crystal display element or the like.

DESCRIPTION OF THE EMBODIMENTS

Hereinbelow, based on the accompanying drawings, an embodiment of thepresent teaching will be explained. FIG. 1 is a diagram schematicallyshowing a configuration of a main part of an illumination optical systemaccording to the embodiment. In FIG. 1, an X-Y-Z coordinate system isdefined such that the Z-axis represents a direction along an opticalaxis AX of the illumination optical system.

In FIG. 1, light from an unshown light source reaches a spatial lightmodulator 3 including a plurality of mirror elements (not shown) whichare arranged within a predetermined plane and controlled individually.The light reflected by the plurality of mirror elements of the spatiallight modulator 3 comes into a pupil plane 4 c of a relay optical system4 via a front-side lens group 4 a of the relay optical system 4.Further, a detailed explanation of the configuration and function of thespatial light modulator 3 will be given later with reference to FIGS. 3and 4. Assuming that, in FIG. 1, an effective reflection region (area)on an arrangement plane (a predetermined plane) of the spatial lightmodulator 3 is divided into four partial regions R01, R02, R03, and R04,only the light from the partial regions R01 and R04 will be explainedhereinbelow in order to simplify the explanation.

The light from the plurality of mirror elements positioned in thepartial region R01 of the spatial light modulator 3 is guided to a pairof pupil regions R1 a and R1 b on the pupil plane 4 c via the front-sidelens group 4 a, to respectively form light intensity distributions P1 aand P1 b within the pupil regions R1 a and R1 b. Further, the light fromthe plurality of mirror elements positioned in the partial region R04 ofthe spatial light modulator 3 is guided to a pair of pupil regions R4 aand R4 b on the pupil plane 4 c via the front-side lens group 4 a, torespectively form light intensity distributions P4 a and P4 b within thepupil regions R4 a and R4 b.

The light from the pupil plane 4 c reaches a region 3 f within a planeoptically conjugate with the arrangement plane of the spatial lightmodulator 3 with respect to the relay optical system 4, via a rear-sidelens group 4 b of the relay optical system 4. On this conjugate plane,there are arranged an optical rotation member 51 to rotate thepolarization direction of a linearly polarized incident light by 45degrees, and an optical rotation member 52 to rotate the polarizationdirection of a linearly polarized incident light by 90 degrees. In FIG.1, the region 3 f is divided into four partial regions R11 to R14optically conjugate with the partial regions R01 to R04 of the spatiallight modulator 3 respectively, and the optical rotation member 51 ispositioned in the partial regions R12 and R13 while the optical rotationmember 52 is positioned in the partial regions R13 and R14.

Here, among the light from the pupil plane 4 c, the light from the pairof pupil regions R4 a and R4 b reaches the partial region R14 within theregion 3 f, and its polarization direction is rotated by 90 degrees bypassing through the optical rotation member 52. On this occasion,because the light from the spatial light modulator 3 is a Y-directionlinearly polarized light having the polarization direction in the Ydirection, the light from the pair of pupil regions R4 a and R4 b passedthe optical rotation member 52 becomes a X-direction linearly polarizedlight having the polarization direction in the X direction. Then, thelights from the pair of pupil regions R4 a and R4 b each of which is thelinearly polarized light of X direction, are guided, via a relay opticalsystem 6, to a pair of pupil regions R14 a and R14 b on a pupil plane 7a optically conjugate with the pupil plane 4 c, to respectively formlight intensity distributions P14 a and P14 b within the pupil regionsR14 a and R14 b.

Further, among the lights from the pupil plane 4 c, the lights from thepair of pupil regions R1 a and R1 b reaches the partial region R11within the region 3 f. Because the optical rotation members 51 and 52are not positioned in this partial region, and the light from thespatial light modulator 3 is a Y-direction linearly polarized lighthaving a polarization direction in the Y direction, the lights from thepair of pupil regions R1 a and R1 b having passed the partial region R11remain the Y-direction linearly polarized light. Then, the light fromthe pair of pupil regions R1 a and R1 b having passed the partial regionR11 is guided, via the relay optical system 6, to a pair of pupilregions R11 a and R11 b on the pupil plane 7 a, to respectively formlight intensity distributions P11 a and P11 b of the Y-directionlinearly polarized light within the pupil regions R11 a and R11 b.

The light from the light intensity distributions P11 a, P11 b, P14 a andP14 b of the pupil plane 7 a is condensed via an unshown condenseroptical system to illuminate an illumination objective plane. Here, ifthe optical rotation members 51 and 52 on the region 3 f within theplane optically conjugate with the arrangement plane of the spatiallight modulator 3 is moved on this region 3 f, then it is possible tochange the polarization state of the light intensity distributions ofthe pupil plane 7 a into any polarization state. Referring to FIG. 2,this aspect will be explained below in detail.

FIG. 2 is a diagram schematically showing a configuration of an exposureapparatus according to the embodiment. In FIG. 2, the members havingidentical or similar functions to those of the members in the embodimentshown in FIG. 1 are denoted by the reference numerals same as those ofthe members in FIG. 1. The Z-axis is defined along the normal directionof a transfer surface (exposure surface) of a wafer W which is aphotosensitive substrate, the Y-axis is defined as in a directionparallel to the page of FIG. 2 within the transfer surface of the waferW, and the X-axis is defined as in a direction perpendicular to the pageof FIG. 2 within the transfer surface of the wafer W, respectively.

Referring to FIG. 2, in the exposure apparatus of this embodiment,exposure light (illumination light) is supplied from a light source 1.As the light source 1, it is possible to use, for example, an ArFexcimer laser light source supplying light of a wavelength of 193 nm, aKrF excimer laser light source supplying light of a wavelength of 248nm, etc. The exposure light (illumination light) emitted from the lightsource 1 is in a polarization state in which a linearly polarized lightis the main component. Here, the polarization state in which a linearlypolarized light is the main component can be defined as a condition inwhich the intensity of the linearly polarized light is 80% or more ofthe entire intensity of the exposure light (illumination light). Thelight emitted from the light source 1 in the +Z direction enters thespatial light modulator 3 after passing through a beam sending unit 2,and being reflected by an optical path bending mirror MR1. The lightemitted in the +Z direction via the spatial light modulator 3 enters therelay optical system 4.

The beam sending unit 2 has a function of guiding the incident lightbeam (light flux) from the light source 1 to the spatial light modulator3 while converting the incident light beam into a light beam having across section of a suitable size and shape and, meanwhile activelycorrecting the positional variation and angular variation of the lightbeam to enter the spatial light modulator 3. Further, the beam sendingunit 2 may also be configured not to convert the incident light beamfrom the light source 1 into a light beam having a cross section of asuitable size and shape. As will be described later, the spatial lightmodulator 3 has a plurality of mirror elements arranged within apredetermined plane and controlled individually, and a drive unitindividually controlling and driving the attitudes of the plurality ofmirror elements based on a control signal from a control system CR. Theconfiguration and function or effect of the spatial light modulator 3will be described later.

The light emitted from the spatial light modulator 3 comes into thepupil plane 4 c of the relay optical system 4 via the front-side lensgroup 4 a of the relay optical system 4. The front-side lens group 4 ais set such that its front focal position is substantially consistentwith the position of the arrangement plane of the spatial lightmodulator 3 for the plurality of mirror elements (to be referred to as“the arrangement plane of the spatial light modulator”, below), whileits back focal position is substantially consistent with the position ofthe pupil plane 4 c. As will be described later, the light having passedthe spatial light modulator 3 variably forms, on the pupil plane 4 c, alight intensity distribution according to the attitudes of the pluralityof mirror elements.

The light which formed the light intensity distribution on the pupilplane 4 c enters a polarization unit 5 via the rear-side lens group 4 bof the relay optical system 4. The polarization unit 5 is arranged in aposition optically conjugate with the arrangement plane of the spatiallight modulator 3, to change the polarization state of part of theincident light beam and emit the light beam. The configuration andfunction or effect of the polarization unit 5 will be described later.

The light having passed through the polarization unit 5 is reflected inthe +Y direction by an optical path bending mirror MR2 after passingthrough the relay optical system 6, to enter a micro fly's eye lens (orfly's eye lens) 7. The rear-side lens group 4 b and the relay opticalsystem 6 set the pupil plane 4 c and the incidence plane of the microfly's eye lens 7 to be optically conjugate with each other. Therefore,on the incidence plane of the micro fly's eye lens 7 arranged at aposition optically conjugate with the pupil plane 4 c, the light havingpassed the spatial light modulator 3 forms a light intensitydistribution corresponding to the light intensity distribution formed onthe pupil plane 4 c.

The micro fly's eye lens 7 is the optical element which is composed of,for example, a large number of micro lenses having the positiverefractive power arranged densely in the longitudinal and lateraldirections. The micro fly's eye lens 7 is constructed by forming a microlens group by applying the etching treatment to a plane-parallel plate.In the micro fly's eye lens, a large number of micro lenses (microrefracting surfaces) are formed integrally without being isolated fromeach other, unlike any fly's eye lens composed of mutually isolated lenselements. However, the micro fly's eye lens is the optical integrator ofthe wavefront division type like the fly's eye lens in that the lenselements are arranged longitudinally and laterally.

The rectangular micro refracting surface, which serves as the unitwavefront dividing surface of the micro fly's eye lens 7, has therectangular shape which is similar to the shape of the illuminationfield to be formed on the mask M (consequently the shape of the exposurearea to be formed on the wafer W). For example, a cylindrical microfly's eye lens can be also used as the micro fly's eye lens 7. Theconstruction and the function of the cylindrical micro fly's eye lens isdisclosed, for example, in U.S. Pat. No. 6,913,373.

The light beam, which is allowed to come into the micro fly's eye lens7, is divided two-dimensionally by a large number of micro lenses, and asecondary light source (substantial surface light source composed of alarge number of small light sources: pupil intensity distribution),which has approximately the same light intensity distribution as thelight intensity distribution formed on the incident surface, is formedon the back focal plane or the illumination pupil defined in thevicinity thereof. The light beam, which comes from the secondary lightsource formed on the illumination pupil defined just downstream from themicro fly's eye lens 7, illuminates a mask blind 9 in a superimposedmanner via a condenser optical system 8.

Thus, an illumination field which has a rectangular shape depending onthe focal distance and the shape of the rectangular micro refractingsurface of the micro fly's eye lens 7, is formed on the mask blind 9 asthe illumination field diaphragm. An illumination aperture diaphragm,which has an aperture (light transmitting portion) having a shapecorresponding to the secondary light source, may be arranged on the backfocal plane of the micro fly's eye lens 7 or in the vicinity thereof,i.e., at the position approximately optically conjugate with theentrance pupil plane of the projection optical system PL described lateron.

The light beam, which passes through the rectangular aperture (lighttransmitting portion) of the mask blind 9, undergoes the lightcollecting action of an imaging optical system 10, and the light beam isreflected in the −Z direction by a mirror MR3 arranged in the opticalpath of the imaging optical system 10. After that, the light beamilluminates the mask M on which a predetermined pattern is formed, in asuperimposed manner. That is, the imaging optical system 10 forms, onthe mask M, the image of the rectangular aperture of the mask blind 9.

The light beam, which passes through the mask M held on a mask stage MS,forms an image of the mask pattern on the wafer (photosensitivesubstrate) W held on a wafer stage WS, via the projection optical systemPL. In this way, the respective exposure areas of the wafer W aresuccessively exposed with the pattern of the mask M by performing thefull field exposure or the scanning exposure while two-dimensionallycontrolling and driving the wafer stage WS in the plane (XY plane)orthogonal to the optical axis AX of the projection optical system PL,and consequently two-dimensionally controlling and driving the wafer W.If the scanning exposure is carried out, then it is possible to set theY direction in FIG. 2 as the scanning direction.

The exposure apparatus of this embodiment is provided with a first pupilintensity distribution measuring unit DTr which measures the pupilintensity distribution on the exit pupil plane of the illuminationoptical system on the basis of the light allowed to pass through theillumination optical system (2 to 10), a second pupil intensitydistribution measuring unit DTw which measures the pupil intensitydistribution on the pupil plane of the projection optical system PL(exit pupil plane of the projection optical system PL) on the basis ofthe light allowed to pass through the projection optical system PL, anda control system CR which controls the spatial light modulator 3 andwhich controls the operation of the exposure apparatus as a whole on thebasis of the measurement result of at least one of the first and secondpupil intensity distribution measuring units DTr, DTw.

The first pupil intensity distribution measuring unit DTr is providedwith an image pickup unit which has a photoelectric conversion surface(plane) arranged, for example, at a position optically conjugate withthe exit pupil position of the illumination optical system, and thefirst pupil intensity distribution measuring unit DTr monitors the pupilintensity distribution in relation to the respective points on theillumination objective surface to be illuminated by the illuminationoptical system (pupil intensity distribution formed at the exit pupilposition of the illumination optical system by the light allowed to comeinto each of the points). Further, the second pupil intensitydistribution measuring unit DTw is provided with an image pickup unitwhich has a photoelectric conversion surface (plane) arranged, forexample, at a position optically conjugate with the pupil position ofthe projection optical system PL, and the second pupil intensitydistribution measuring unit DTw monitors the pupil intensitydistribution in relation to the respective points on the image plane ofthe projection optical system PL (pupil intensity distribution formed atthe pupil position of the projection optical system PL by the lightallowed to come into each of the points).

Reference can be made, for example, to United States Patent ApplicationPublication No. 2008/0030707 about detailed constructions and functionsof the first and second pupil intensity distribution measuring unitsDTr, DTw. Reference can be also made to the disclosure of United StatesPatent Application Publication No. 2010/0020302 in relation to the pupilintensity distribution measuring unit.

In this embodiment, the mask M arranged on the illumination objectivesurface of the illumination optical system (consequently the wafer W) issubjected to the Koehler illumination by using the light source of thesecondary light source formed by the micro fly's eye lens 7. Therefore,the position, at which the secondary light source is formed, isoptically conjugate with the position of the aperture diaphragm AS ofthe projection optical system PL. The plane or surface, on which thesecondary light source is formed, can be referred to as the illuminationpupil plane of the illumination optical system. Further, the image ofthe plane (surface) on which the secondary light source is formed can bereferred to as the exit pupil plane of the illumination optical system.Typically, the illumination objective surface (surface or plane on whichthe mask M is arranged, or the surface or plane on which the wafer W isarranged when the illumination optical system is regarded as includingthe projection optical system PL) is the optical Fourier transform plane(surface) with respect to the illumination pupil plane. The pupilintensity distribution is the light intensity distribution (luminancedistribution) on the illumination pupil plane of the illuminationoptical system or the plane (surface) optically conjugate with theillumination pupil plane.

When the number of wavefront division by the micro fly's eye lens 7 isrelatively large, the macroscopic (broader basis) light intensitydistribution, which is formed on the incident surface of the micro fly'seye lens 7, exhibits the high correlation with respect to themacroscopic (broader basis) light intensity distribution (pupilintensity distribution) of the entire secondary light source. Therefore,the light intensity distribution, which is provided on the incidentsurface of the micro fly's eye lens 7 or the surface or plane opticallyconjugate with the incident surface concerned, can be also referred toas the pupil intensity distribution. In the construction shown in FIG.2, the relay optical systems 4, 6 and the micro fly's eye lens 7constitute a distribution formation optical system for forming the pupilintensity distribution on the illumination pupil defined just downstreamfrom the micro fly's eye lens 7 on the basis of the light beam allowedto pass through the spatial light modulator 3.

Next, the configuration and function or effect of the spatial lightmodulator 3 will be explained specifically. As shown in FIG. 3, thespatial light modulator 3 includes a plurality of mirror elements 3 aarranged within a predetermined plane, a base 3 b holding the pluralityof mirror elements 3 a, and a drive portion 3 c individually controllingand driving the attitudes of the plurality of mirror elements 3 a via acable (not shown) connected to the base 3 b. In the spatial lightmodulator 3, by the function of the drive portion 3 c operating based oncommands from the control system CR, the attitudes of the plurality ofmirror elements 3 a change respectively, and each of the plurality ofmirror elements 3 a is set respectively in a predetermined direction.

As shown in FIG. 4, the spatial light modulator 3 is provided with aplurality of micro mirror elements 3 a which are aligned (arranged)two-dimensionally, and the spatial light modulator 3 variably gives thespatial modulation to the incident light, the spatial modulationdepending on the incident position of the incident light, and then emitthe modulated light. In order to simplify the explanation and theillustration, FIGS. 3 and 4 show an exemplary construction in which thespatial light modulator 3 is provided with 4×4=16 pieces of the mirrorelements 3 a. However, actually, the spatial light modulator 3 isprovided with a large number of mirror elements 3 a, the number beingmuch larger than sixteen.

With reference to FIG. 3, as for those of the light beam group allowedto come into the spatial light modulator 3, the light beam L1 comes intothe mirror element SEa of the plurality of mirror elements 3 a, and thelight beam L2 comes into the mirror element SEb different from themirror element SEa. Similarly, the light beam L3 comes into the mirrorelement SEc different from the mirror elements SEa, SEb, and the lightbeam L4 comes into the mirror element SEd different from the mirrorelements SEa to SEc. The mirror elements SEa to SEd give the spatialmodulations set depending on the positions thereof, to the light beamsL1 to L4.

The spatial light modulator 3 is configured such that in a referencestate in which all reflecting surfaces of the mirror elements 3 a is setalong one plane, the incident light beam along a direction parallel tothe optical axis AX of the optical path between the mirror MR1 and thespatial light modulator 3 are reflected by the spatial light modulator 3and, thereafter, propagates in a direction parallel to the optical axisAX of the optical path between the spatial light modulator 3 and therelay optical system 4. Further, as described above, the arrangementplane of the spatial light modulator 3 for the plurality of mirrorelements 3 a is positioned at the front focal position of the front sidelens group 4 a of the relay optical system 4, or in its vicinity.

Therefore, the light beams, which are reflected by the plurality ofmirror elements SEa to SEd of the spatial light modulator 3 and to whichpredetermined angle distributions are given, form predetermined lightintensity distributions SP1 to SP4 on the pupil plane 4 c of the relayoptical system 4, and the light beams consequently form light intensitydistribution corresponding to the light intensity distributions SP1 toSP4 on the incident surface of the micro fly's eye lens 7. That is, theangles, which are given by the plurality of mirror elements SEa to SEdof the spatial light modulator 3 to the outgoing light, are converted bythe front side lens group 4 a into the positions on the pupil plane 4 cwhich is the far field of the spatial light modulator 3 (Fraunhoferdiffraction area). Thus, the light intensity distribution (pupilintensity distribution) of the secondary light source formed by themicro fly's eye lens 7 is the distribution corresponding to the lightintensity distribution formed on the incident surface of the micro fly'seye lens 7 by the spatial light modulator 3 and the relay opticalsystems 4, 6.

As shown in FIG. 4, the spatial light modulator 3 is the movablemulti-mirror including the mirror elements 3 a which are the largenumber of micro reflecting elements arranged or aligned regularly andtwo-dimensionally along one flat surface or plane in the state in whichthe planar reflecting surfaces are the upper surfaces. The respectivemirror elements 3 a are movable. The inclinations of the reflectingsurfaces thereof, i.e., the angles of inclination and the directions ofinclination of the reflecting surfaces are independently controlled bythe action of the driving unit 3 c operated on the basis of the controlsignal fed from the control system CR. Each of the mirror elements 3 acan be rotated continuously or discretely by a desired angle of rotationabout the rotation axes in the two directions parallel to the reflectingsurface thereof, the two directions being perpendicular to one another.That is, the inclination of the reflecting surface of each of the mirrorelements 3 a can be controlled two-dimensionally.

When the reflecting surface of each of the mirror elements 3 a isrotated discretely, it is appropriate to control the angle of rotationsuch that the angle is switched among a plurality of states (forexample, . . . , −2.5 degrees, −2.0 degrees, . . . , 0 degree, +0.5degree, . . . , +2.5 degrees, . . . ). FIG. 4 shows the mirror elements3 a having square contours. However, the contour shape of the mirrorelement 3 a is not limited to the square. However, in view of the lightutilization efficiency, it is possible to adopt a shape (shape capableof close packing) in which the mirror elements 3 a can be arranged sothat the gap between the mirror elements 3 a is decreased. Further, inview of the light utilization efficiency, the spacing distance betweenthe two adjoining mirror elements 3 a can be suppressed to be minimumrequirement.

In this embodiment, for example, the spatial light modulator, in whichthe directions of the plurality of mirror elements 3 a arrangedtwo-dimensionally are changed continuously respectively, is used as thespatial light modulator 3. As for the spatial light modulator asdescribed above, it is possible to use any spatial light modulatordisclosed, for example, in European Patent Application Publication No.779530, U.S. Pat. Nos. 5,867,302, 6,480,320, 6,600,591, 6,733,144,6,900,915, 7,095,546, 7,295,726, 7,424,330, and 7,567,375, United StatesPatent Application Publication No. 2008/0309901, International PatentApplication Publication Nos. WO2010/037476 and WO2010/040506, andJapanese Patent Application Laid-open No. 2006-113437. The directions ofthe plurality of mirror elements 3 a arranged two-dimensionally may becontrolled discretely and in multistage manner.

In the spatial light modulator 3, the attitudes of the plurality ofmirror elements 3 a are changed respectively by the action of thedriving unit 3 c operated in response to the control signal suppliedfrom the control system CR, and the respective mirror elements 3 a areset in the predetermined directions. The light beams, which arereflected at the predetermined angles respectively by the plurality ofmirror elements 3 a of the spatial light modulator 3, form the desiredpupil intensity distribution on the illumination pupil defined justdownstream from the micro fly's eye lens 7. Further, the desired pupilintensity distribution is also formed at positions of other illuminationpupils optically conjugate with the illumination pupil defined justdownstream from the micro fly's eye lens 7, i.e., at the pupil positionof the imaging optical system 10 and the pupil position of theprojection optical system PL (position at which the aperture diaphragmAS is arranged). In other words, the spatial light modulator 3 variablyforms the pupil intensity distribution in the illumination pupil justdownstream from the micro fly's eye lens 7.

As described above, the polarization unit 5 is arranged in a positionoptically conjugate with the arrangement plane of the spatial lightmodulator 3. Therefore, the property of the light beam coming into thepolarization unit 5 corresponds to the property of the light beam cominginto the spatial light modulator 3. Hereinbelow, in order to facilitatecomprehension of the explanation, a parallel light beam of a linearlypolarized light, which has a rectangular cross section elongate in the Xdirection and is polarized in the Y direction (to be referred to as “theY direction linearly polarized light”, below), is supposed to come intothe polarization unit 5. Hence, the parallel light beam of the linearlypolarized light, which has a rectangular cross section elongate in the Xdirection and is polarized in a direction parallel to the page of FIG.1, comes into the spatial light modulator 3.

As shown in FIG. 5, the polarization unit 5 includes the pair of opticalrotation members 51 and 52 arranged to be adjacent to each other alongthe optical axis AX and movable respectively along the X direction whichis a direction along the cross section of the incident light, and driveportions DR51 and DR52 provided to move the pair of optical rotationmembers 51 and 52 in the X direction. The optical rotation members 51and 52 are formed of a crystalline material which is an optical materialhaving a form of plane parallel plate and having optical rotationproperty, for example, crystal. The incident surfaces (and,consequently, the emission surfaces) of the optical rotation members 51and 52 are orthogonal to the optical axis AX, and their crystallineoptic axes are substantially consistent with the direction of theoptical axis AX (i.e., substantially consistent with the Z directionwhich is the propagation direction of the incident light). Further, thedrive portions DR51 and DR52 include actuators for moving the opticalrotation members 51 and 52, and encoders for detecting the movementamounts of the optical rotation members 51 and 52, so as to move theoptical rotation members 51 and 52 based on the control signals from thecontrol system CR.

As shown in FIG. 6, the optical rotation members 51 and 52 each have arectangular outer shape (contour) with one pair of sides along the Xdirection and the other pair of sides along the Y direction. In otherwords, the optical rotation members 51 and 52 have a pair of edges 51 aand 51 b and a pair of edges 52 a and 52 b along the Y direction,respectively. The optical rotation members 51 and 52 are different inthickness from each other and, consequently, different in polarizationtransformation property (polarization conversion property) from eachother.

In particular, the optical rotation member 51 is set at such a thicknessas to emit a linearly polarized light having the polarization directionin a +45 degree oblique direction obtained by rotating the Y directionby +45 degrees (45 degrees clockwise on the page of FIG. 6), on theincidence of a Y direction linearly polarized light having thepolarization direction in the Y direction. On the other hand, theoptical rotation member 52 arranged adjacent to the optical rotationmember 51 on the emission side is set at such a thickness as to emit a Xdirection linearly polarized light having the polarization direction inthe X direction, which is the direction obtained by rotating the Ydirection by +90 degrees, on the incidence of a Y direction linearlypolarized light.

As shown in FIG. 6, a parallel light beam F1 of the Y direction linearlypolarized light having a rectangular cross section elongated in the Xdirection with the optical axis AX as the center coming into thepolarization unit 5. In this case, among the incident light beam F1, afirst partial light beam F11 having a rectangular cross section, i.e.,the light beam on the +X direction side of the +X direction side edge 51b of the optical rotation member 51 propagates toward the relay opticalsystem 6 without passing through the optical rotation members 51 or 52.A second partial light beam F12 having a rectangular cross sectionadjacent to the first partial light beam F11, i.e., the light beamdefined by the +X direction side edge 51 b of the optical rotationmember 51 and the +X direction side edge 52 b of the optical rotationmember 52 propagates toward the relay optical system 6 via only theoptical rotation member 51 without passing through the optical rotationmember 52.

A third partial light beam F13 having a rectangular cross sectionadjacent to the second partial light beam F12, i.e., the light beamdefined by the −X direction side edge 51 a of the optical rotationmember 51 and the +X direction side edge 52 b of the optical rotationmember 52 propagates toward the relay optical system 6 via the opticalrotation members 51 and 52. A fourth partial light beam F14 having arectangular cross section adjacent to the third partial light beam F13,i.e., the light beam on the −X direction side of the −X direction sideedge 51 a of the optical rotation member 51 propagates toward the relayoptical system 6 via only the optical rotation member 52 without passingthrough the optical rotation member 51.

As a result, the light beam F1 at a position just downstream from thepolarization unit 5 has such a polarization state as shown in FIG. 7.That is, because the first partial light beam F11 does not receive theoptical rotation effects of the optical rotation members 51 and 52, itremains the Y direction linearly polarized light as it is. Because thesecond partial light beam F12 receives only the optical rotation effectof the optical rotation member 51, it becomes a linearly polarized lightof +45 degree oblique direction having the polarization direction in adirection obtained by rotating the Y direction by +45 degrees.

Because the fourth partial light beam F14 receives only the opticalrotation effect of the optical rotation member 52, it becomes a Xdirection linearly polarized light having the polarization direction inthe X direction obtained by rotating the Y direction by +90 degrees. Thethird partial light beam F13 successively receives the optical rotationeffect of the optical rotation member 51 and the optical rotation effectof the optical rotation member 52. Therefore, the third partial lightbeam F13 becomes a linearly polarized light of −45 degree obliquedirection having the polarization direction in a direction obtained byrotating the Y direction by −45 degrees, i.e., a direction obtained byrotating the Y direction by +45 degrees, and further rotating by +90degrees.

As shown in FIG. 8, a partial region R11 occupied by the first partiallight beam F11 in the polarization unit 5 corresponds to the rectangularpartial region R01 in an effective refection region on the arrangementplane of the spatial light modulator 3. Likewise, partial regions R12,R13 and R14 occupied by the partial light beams F12, F13 and F14correspond to the rectangular partial regions R02, R03 and R04,respectively. A rectangular region R0 circumscribing the partial regionsR01 to R04 on the arrangement plane of the spatial light modulator 3corresponds to the region R1 occupied by the incident light beam F1 inthe polarization unit 5.

In this embodiment, the drive portion 3 c controls the respectiveattitudes of the plurality of mirror elements 3 a belonging to a firstmirror element group S01 positioned in the first partial region R01,among the plurality of mirror elements 3 a of the spatial lightmodulator 3, to guide the light via the first mirror element group S01to the pair of pupil regions R11 a and R11 b on the illumination pupilplane just downstream from the micro fly's eye lens 7, as shown in FIG.9A. As described above, the illumination pupil plane just downstreamfrom the micro fly's eye lens 7 is a plane optically conjugate with thepupil plane 4 c of the relay optical system 4 and, furthermore, anoptical Fourier transform plane of the arrangement plane of the spatiallight modulator 3. The pair of pupil regions R11 a and R11 b are, forexample, regions spaced in the X direction with the optical axis AXintervening therebetween.

The drive portion 3 c controls the respective attitudes of the pluralityof mirror elements 3 a belonging to a fourth mirror element group S04positioned in the fourth partial region R04, to guide the light via thefourth mirror element group S04 to the pair of pupil regions R14 a andR14 b on the illumination pupil plane. The pair of pupil regions R14 aand R14 b are, for example, regions spaced in the Z direction with theoptical axis AX intervening therebetween. The drive portion 3 c controlsthe respective attitudes of the plurality of mirror elements 3 abelonging to a second mirror element group S02 positioned in the secondpartial region R02, and controls the respective attitudes of theplurality of mirror elements 3 a belonging to a third mirror elementgroup S03 positioned in the third partial region R03, to guide the lightvia the third and fourth mirror element groups S03 and S04 to the pairof pupil regions R12 a and R12 b and the pair of pupil regions R13 a andR13 b on the illumination pupil plane, respectively.

The pair of pupil regions R12 a and R12 b are, for example, regionsspaced in a direction at an angle of 45 degrees to the −X direction aswell as to the +Z direction with the optical axis AX interveningtherebetween. The pair of pupil regions R13 a and R13 b are, forexample, regions spaced in a direction at an angle of 45 degrees to the+X direction as well as to the +Z direction with the optical axis AXintervening therebetween. In this manner, based on the parallel lightbeam having a rectangular cross section, the spatial light modulator 3forms, for example, an eight pole-shaped pupil intensity distribution 21a which is composed of eight circular substantive surface light sourcesP11 a and P11 b, P12 a and P12 b, P13 a and P13 b, and P14 a and P14 b,in the illumination pupil just downstream from the micro fly's eye lens7.

That is, the light via the first mirror element group S01 of the spatiallight modulator 3 forms the surface light sources P11 a and P11 boccupying the pupil regions R11 a and R11 b without passing through theoptical rotation members 51 and 52 of the polarization unit 5. Becausethe light forming the pair of surface light sources P11 a and P11 b doesnot pass through the optical rotation members 51 and 52, it is a Zdirection linearly polarized light (corresponding to the Y directionlinearly polarized light in FIG. 7). The light via the fourth mirrorelement group S04 forms the surface light sources P14 a and P14 boccupying the pupil regions R14 a and R14 b only via the opticalrotation member 52 without passing through the optical rotation member51. Because the light forming the pair of surface light sources P14 aand P14 b only passes through the optical rotation member 52, it is a Xdirection linearly polarized light (corresponding to the X directionlinearly polarized light in FIG. 7).

The light via the second mirror element group S02 forms the surfacelight sources P12 a and P12 b occupying the pupil regions R12 a and R12b only via the optical rotation member 51 without passing through theoptical rotation member 52. Because the light forming the pair ofsurface light sources P12 a and P12 b only passes through the opticalrotation member 51, it is a linearly polarized light of +45 degreeoblique direction having the polarization direction in a directionobtained by rotating the Z direction clockwise by +45 degrees on thepage of FIG. 9A (corresponding to the linearly polarized light of +45degree oblique direction in FIG. 7).

The light via the third mirror element group S03 forms the surface lightsources P13 a and P13 b occupying the pupil regions R13 a and R13 b viathe optical rotation member 51 and the optical rotation member 52.Because the light forming the pair of surface light sources P13 a andP13 b passes through both of the optical rotation members 51 and 52, itis a linearly polarized light of −45 degree oblique direction having thepolarization direction in a direction obtained by rotating the Zdirection clockwise by −45 degrees on the page of FIG. 9A (correspondingto the linearly polarized light of −45 degree oblique direction in FIG.7).

In this manner, by the collaboration of the spatial light modulator 3and the polarization unit 5, the eight pole-shaped pupil intensitydistribution 21 a in a circumferential direction polarization state isformed in the illumination pupil just downstream from the micro fly'seye lens 7. Further, an eight pole-shaped pupil intensity distributionin a circumferential direction polarization state corresponding to thepupil intensity distribution 21 a is also formed at a position ofanother illumination pupil optically conjugate with the illuminationpupil just downstream from the micro fly's eye lens 7, i.e., at thepupil position of the image formation optical system 10, and at thepupil position of the projection optical system PL (the position atwhich the aperture stop AS is arranged).

In general, in the case of the circumferential direction polarizedillumination based on the annular or multi-pole-shaped (for example, twopole-shaped, four pole-shaped or eight pole-shaped) pupil intensitydistribution in the circumferential direction polarization state, thelight, which is radiated onto the wafer W as the final illuminationobjective surface, is in the polarization state in which the s-polarizedlight is the main component. In this case, the s-polarized light is thelinearly polarized light having the polarization direction in thedirection perpendicular to the plane of incidence (polarized lighthaving the electric vector vibrating in the direction perpendicular tothe plane of incidence). The plane of incidence is defined as the planewhich includes the light incident direction and the normal line of theboundary surface at the point provided when the light arrives at theboundary surface of the mediums (illumination objective surface (plane):surface of the wafer W). As a result, in the case of the circumferentialdirection polarized illumination, it is possible to improve the opticalperformance (for example, the depth of focus) of the projection opticalsystem, and it is possible to obtain the mask pattern image having thehigh contrast on the wafer (photosensitive substrate).

Now, in this embodiment, as shown in FIG. 9B for example, it is possibleto form an eight pole-shaped pupil intensity distribution 21 b having apolarization distribution different from that of the eight pole-shapedpupil intensity distribution 21 a. This eight pole-shaped pupilintensity distribution 21 b is composed, for example, of eight circularsubstantive surface light sources P11 a and P11 b, P12 a and P12 b, P13a and P13 b, and P14 a and P14 b, and has a polarization distributionobtained by rotating the polarization directions of the surface lightsources P12 a and P12 b, and P13 a and P13 b in the pupil intensitydistribution 21 a by 90 degrees.

In order to form the pupil intensity distribution 21 b shown in FIG. 9B,it is possible to set, for example, the respective attitudes of theplurality of mirror elements 3 a belonging to the second mirror elementgroup S02 positioned in the second partial region R02 such that thelight via the second mirror element group S02 may be guided to the pairof pupil regions R13 a and R13 b on the illumination pupil plane, andset the respective attitudes of the plurality of mirror elements 3 abelonging to the third mirror element group S03 positioned in the thirdpartial region R03 such that the light via the third mirror elementgroup S03 may be guided to the pair of pupil regions R12 a and R12 b onthe illumination pupil plane.

Further, it is also possible to form the pupil intensity distribution 21b shown in FIG. 9B by positioning the optical rotation member 52 tocover the partial regions R11 and R12 occupied by the first and secondpartial light beams F11 and F12, and letting the X direction linearlypolarized light enter the polarization unit 5 (or the spatial lightmodulator 3). Further, for the technique of controlling the polarizationdirection or degree of polarization of the light coming into thepolarization unit 5 (or the spatial light modulator 3), reference can bemade to a polarized state switching portion disclosed in U.S. Pat. No.7,423,731.

In this embodiment, because of use of the spatial light modulator 3having the large number of mirror elements 3 a whose attitudes arecontrolled individually, there is a high degree of freedom in changingthe shape (broad concept including the size) of the pupil intensitydistribution. As an example, by only controlling the spatial lightmodulator 3 according to a command from the control system CR, as shownin FIG. 10, it is possible to form an annular pupil intensitydistribution 22 in a circumferential direction polarization state in theillumination pupil just downstream from the micro fly's eye lens 7.

In the example shown in FIG. 10, the light via the first mirror elementgroup S01 is guided to a pair of arc-like pupil regions R21 a and R21 bspaced in the X direction across the optical axis AX on the illuminationpupil plane, to form substantial surface light sources P21 a and P21 b.The light via the fourth mirror element group S04 is guided to a pair ofarc-like pupil regions R24 a and R24 b spaced in the Z direction acrossthe optical axis AX, to form substantial surface light sources P24 a andP24 b. The light via the second mirror element group S02 is guided to apair of arc-like pupil regions R22 a and R22 b spaced in a direction atan angle of 45 degrees to the −X direction as well as to the +Zdirection across the optical axis AX, to form substantial surface lightsources P22 a and P22 b.

The light via the third mirror element group S03 is guided to a pair ofarc-like pupil regions R23 a and R23 b spaced in a direction at an angleof 45 degrees to the +X direction as well as to the +Z direction acrossthe optical axis AX, to form substantial surface light sources P23 a andP23 b. The pupil regions R21 a and R21 b, R22 a and R22 b, R23 a and R23b, and R24 a and R24 b are arc-like regions obtained by dividing theannular region around the optical axis AX into eight parts along thecircumferential direction. In this manner, the annular pupil intensitydistribution 22 in a circumferential direction polarization state isformed from, for example, eight arc-like substantive surface lightsources P21 a and P21 b, P22 a and P22 b, P23 a and P23 b, and P24 a andP24 b.

Further, in this embodiment, because of use of the spatial lightmodulator 3 having the large number of mirror elements 3 a whoseattitudes are controlled individually, there is a high degree of freedomin changing the polarization state of the pupil intensity distribution.As an example, by only controlling the spatial light modulator 3according to a command from the control system CR, as shown in FIG. 11,it is possible to form an eight pole-shaped pupil intensity distribution23 in a radial direction polarization state in the illumination pupiljust downstream from the micro fly's eye lens 7.

In the example shown in FIG. 11, the light via the first mirror elementgroup S01 forms surface light sources P31 a and P31 b occupying thepupil regions R14 a and R14 b on the illumination pupil plane withoutpassing through the optical rotation members 51 and 52. Because thelight forming the pair of surface light sources P31 a and P31 b does notpass through the optical rotation members 51 and 52, it is a Z directionlinearly polarized light. The light via the fourth mirror element groupS04 forms surface light sources P34 a and P34 b occupying the pupilregions R11 a and R11 b via only the optical rotation member 52 withoutpassing through the optical rotation member 51. Because the lightforming the pair of surface light sources P34 a and P34 b only passesthrough the optical rotation member 52, it is a X direction linearlypolarized light.

The light via the second mirror element group S02 forms surface lightsources P32 a and P32 b occupying the pupil regions R13 a and R13 b viaonly the optical rotation member 51 without passing through the opticalrotation member 52. Because the light forming the pair of surface lightsources P32 a and P32 b only passes through the optical rotation member51, it is a linearly polarized light of +45 degree oblique directionhaving the polarization direction in a direction obtained by rotatingthe Z direction clockwise by +45 degrees on the page of FIG. 11.

The light via the third mirror element group S03 forms surface lightsources P33 a and P33 b occupying the pupil regions R12 a and R12 b viathe optical rotation member 51 and the optical rotation member 52.Because the light forming the pair of surface light sources P33 a andP33 b passes through both of the optical rotation members 51 and 52, itis a linearly polarized light of −45 degree oblique direction having thepolarization direction in a direction obtained by rotating the Zdirection clockwise by −45 degrees on the page of FIG. 11.

In this manner, the eight pole-shaped pupil intensity distribution 23 ina radial direction polarization state is formed from, for example, eightcircular substantial surface light sources P31 a and P31 b, P32 a andP32 b, P33 a and P33 b, and P34 a and P34 b. Although not shown in thedrawings, it is also possible to form an annular pupil intensitydistribution in a radial direction polarization state in theillumination pupil just downstream from the micro fly's eye lens 7 byonly controlling the spatial light modulator 3 according to a commandfrom the control system CR.

In general, in the case of the radial direction polarized illuminationbased on the annular or multi-pole-shaped pupil intensity distributionin the radial direction polarization state, the light, which is radiatedonto the wafer W as the final illumination objective surface, is in thepolarization state in which the p-polarized light is the main component.In this case, the p-polarized light is the linearly polarized lighthaving the polarization direction in the direction parallel to the planeof incidence defined as described above (polarized light having theelectric vector vibrating in the direction parallel to the plane ofincidence). As a result, in the case of the radial direction polarizedillumination, the reflectance of the light can be suppressed to be smallon the resist with which the wafer W is coated, and it is possible toobtain the satisfactory image of the mask pattern on the wafer(photosensitive substrate).

Further, in this embodiment, by the effect of the spatial lightmodulator 3, it is possible to relatively change the light intensitybetween, for example, the respective pairs of surface light sources: P11a and P11 b, P12 a and P12 b, P13 a and P13 b, and P14 a and P14 b amongthe eight surface light sources constituting the eight pole-shaped pupilintensity distribution 21 a while maintaining the circumferentialdirection polarization state. However, it is not possible to relativelychange the light intensity between, for example, the surface lightsource P11 a and a light source other than the light source P11 b whilemaintaining the polarization state by the effect of the spatial lightmodulator 3 alone.

In this embodiment, however, by the collaboration of the spatial lightmodulator 3 and the polarization unit 5, it is possible to relativelychange the light intensity among, for example, the eight surface lightsources constituting the eight pole-shaped pupil intensity distribution21 a while maintaining the circumferential direction polarization state.In particular, if only the optical rotation member 51 is moved from theposition shown in FIG. 6 toward the +X direction side, then thecross-sectional area of the first partial light beam F11 (the area ofthe partial region R11) decreases, whereas the cross-sectional area ofthe second partial light beam F12 (the area of the partial region R12)increases. As a result, it is possible to lower the light intensity ofthe pair of surface light sources P11 a and P11 b, and raises the lightintensity of the pair of surface light sources P12 a and P12 b.

If only the optical rotation member 51 is moved from the position shownin FIG. 6 toward the −X direction side, then the cross-sectional area ofthe second partial light beam F12, and the cross-sectional area of thefourth partial light beam F14 (the area of the partial region R14)decrease, whereas the cross-sectional area of the first partial lightbeam F11, and the cross-sectional area of the third partial light beamF13 (the area of the partial region R13) increase. As a result, it ispossible to lower the light intensity of the pair of surface lightsources P12 a and P12 b and the light intensity of the pair of surfacelight sources P14 a and P14 b, and raises the light intensity of thepair of surface light sources P11 a and P11 b and the light intensity ofthe pair of surface light sources P13 a and P13 b.

If only the optical rotation member 52 is moved from the position shownin FIG. 6 toward the +X direction side, then the cross-sectional area ofthe second partial light beam F12 decreases, whereas the cross-sectionalarea of the third partial light beam F13 increases. As a result, it ispossible to lower the light intensity of the pair of surface lightsources P12 a and P12 b, and raises the light intensity of the pair ofsurface light sources P13 a and P13 b. If only the optical rotationmember 52 is moved from the position shown in FIG. 6 toward the −Xdirection side, then the cross-sectional area of the third partial lightbeam F13 decreases, whereas the cross-sectional area of the secondpartial light beam F12 increases. As a result, it is possible to lowerthe light intensity of the pair of surface light sources P13 a and P13b, and raises the light intensity of the pair of surface light sourcesP12 a and P12 b.

In this manner, by moving at least one of the pair of optical rotationmembers 51 and 52 in the X direction, it is possible to change the ratiobetween the cross-sectional area of the first partial light beam F11,the cross-sectional area of the second partial light beam F12, thecross-sectional area of the third partial light beam F13, and thecross-sectional area of the fourth partial light beam F14. Consequently,it is possible to relatively change the light intensities between theeight surface light sources P11 a and P11 b, P12 a and P12 b, P13 a andP13 b, and P14 a and P14 b which constitute the eight pole-shaped pupilintensity distribution 21 a while maintaining the circumferentialdirection polarization state. Likewise, for the annular pupil intensitydistribution 22 and for the eight pole-shaped pupil intensitydistribution 23, it is also possible to relatively change the lightintensities between the plurality of surface light sources whilemaintaining the polarization state.

Further, in this embodiment, the polarization state of each surfacelight source constituting the pupil intensity distribution is setrespectively by the polarization unit 5 arranged in a position opticallyconjugate with the arrangement plane of the spatial light modulator 3.As a result, it is possible to reduce the adverse influence due todefocus at the edges of the polarization members of the polarizationunit 5 (the optical rotation members 51 and 52), thereby allowing for adesired polarization state of each surface light source constituting thepupil intensity distribution. For comparison, in a method in which thepolarization unit 5 is arranged in a position defocused from theposition optically conjugate with the arrangement plane of the spatiallight modulator, the light passed through the polarization members(optical rotation members) through which the light toward a specificsurface light source should pass is subjected to coexistence with thelight passed through another polarization members (optical rotationmembers) through which the light toward another specific surface lightsource should pass. Hence, the polarization state of the specificsurface light source deviates from the desired polarization state and,consequently, this adversely affects the polarization state of the pupilintensity distribution.

Further, in this embodiment, the polarization state of each surfacelight source constituting the pupil intensity distribution is setrespectively by the polarization unit 5 arranged in the positionoptically conjugate with the arrangement plane of the spatial lightmodulator 3 in the optical path defined on the illumination objectivesurface side of the spatial light modulator 3. As a result, it ispossible to reduce the degree of elliptical polarization of the linearlypolarized light of an oblique direction (a direction different from theX direction and the Z direction on the pupil plane (X-Z plane) in FIG.2) due to the retardation (a phenomenon that phase difference occursbetween a pair of linearly polarized light components whose polarizationdirections are orthogonal to each other) caused by a succeeding opticalsystem arranged in the illumination optical path on the downstream sidefrom the spatial light modulator 3 (the illumination objective surfaceside).

Especially, it is liable to be elliptical polarization that a linearlypolarized light (obliquely polarized light) having a polarizationdirection not along the plane (the Y-Z plane) including the optical axesupstream and downstream of the arrangement plane of the spatial lightmodulator 3, or the plane (the X-Z plane) orthogonal to that plane (theY-Z plane) and including the optical axis.

Here, by causing the linearly polarized light of longitudinal direction(Y direction in FIG. 2) or the linearly polarized light of transversedirection (X direction in FIG. 2) which are typically less liable toreceive the influence of retardation to pass through the illuminationoptical path from the light source to the polarization unit 5,elliptical polarization of the linearly polarized light is less likelyto occur in this optical path.

In the above manner, in the illumination optical system (2 to 10) ofthis embodiment, it is possible to realize a high degree of freedom inchanging the shape and polarization state of the pupil intensitydistribution formed in the illumination pupil just downstream from themicro fly's eye lens 7 without accompanying any replacement of opticalmembers. In the exposure apparatus (2 to WS) of this embodiment, byusing the illumination optical system (2 to 10) having a high degree offreedom in changing the shape and polarization state of the pupilintensity distribution, it is possible to correctly transfer the finepattern to wafer W under a proper illumination condition realizedaccording to the property of the pattern of the mask M to betransferred.

In the embodiment described above, the control system CR can beconstructed by using, for example, a so-called work station (or amicrocomputer) composed of, for example, CPU (central processing unit),ROM (read only memory), and RAM (random access memory), and the controlsystem CR can control the entire apparatus as a whole. Further, thecontrol system CR may be externally connected with a storage devicecomposed of, for example, a hard disk, an input device including, forexample, a keyboard and a pointing device such as a mouse or the like, adisplay device including, for example a CRT display (or a liquid crystaldisplay), and a drive device for an information storage mediumincluding, for example, CD (compact disc), DVD (digital versatile disc),MO (magneto-optical disc), and FD (flexible disc).

In this embodiment, the storage device may be stored, for example, withthe information regarding the pupil intensity distribution (illuminationlight source shape) by which the imaging state of the projection imageprojected onto the wafer W by the projection optical system PL isoptimized (for example, the aberration or the line width is within theallowable range), and the control information for the illuminationoptical system, especially the mirror elements of the spatial lightmodulator 3 corresponding thereto. An information storage medium(referred to as “CD-ROM” for the purpose of convenience in the followingexplanation), in which the programs or the like for performing a settingof the pupil intensity distribution as described later on are stored,may be set to the drive device. It is also allowable that the programsas described above may be installed to the storage device. The controlsystem CR appropriately reads the programs onto the memory.

The control system CR is able to control the spatial light modulator 3and the polarization unit 5 through, for example, the followingprocedure. Further, in the following explanation, the exposure apparatusof this embodiment is supposed to form a pupil intensity distribution 21c shown in FIG. 12. The pupil intensity distribution 21 c of FIG. 12 iscomposed of the eight substantial surface light sources P11 a and P11 b,P12 a and P12 b, P13 a and P13 b, and P14 a and P14 b, where the pair ofsurface light sources P11 a and P11 b are Z direction linearly polarizedlight, the pair of surface light sources P14 a and P14 b are X directionlinearly polarized light, the pair of surface light sources P12 a andP12 b are linearly polarized light of −45 degree oblique direction, andthe pair of surface light sources P13 a and P13 b are linearly polarizedlight of +45 degree oblique direction. Further, the surface lightsources P12 a and P12 b, and P13 a and P13 b have twice the lightintensity of the surface light sources P11 a and P11 b, and P14 a andP14 b.

The pupil intensity distribution can be expressed, for example, in sucha form (bit-map form in a broad sense) that the pupil intensitydistribution is expressed as numerical values using (based on) the lightintensity and the polarizing state of each compartment, each compartmentbeing obtained by dividing the pupil plane into a plurality ofcompartments in a lattice form. It is now assumed that the number ofmirror elements of the spatial light modulator 3 is N and the number ofdivided compartments of the pupil intensity distribution is M. On thisassumption, the pupil intensity distribution (secondary light source) isformed (set) by appropriately combining N pieces of the light beamsreflected by the individual mirror elements so that the light beams areguided to M pieces of the compartments, in other words, by appropriatelyoverlapping (overlaying) N pieces of the light beams on M pieces ofbright spots made up by M pieces of the compartments.

First, from the storage device, the control system CR reads outinformation concerning the target pupil intensity distribution 21 c.Next, from the read-out information concerning the pupil intensitydistribution 21 c, the control system CR calculates how many light beamsare needed respectively for forming the intensity distributionsaccording to each polarization state as shown in FIGS. 13A to 13D forexample. FIG. 13A shows a pupil intensity distribution of the Zdirection linearly polarized light, FIG. 13B shows a pupil intensitydistribution of the X direction linearly polarized light, FIG. 13C showsa pupil intensity distribution of the linearly polarized light of −45degree oblique direction, and FIG. 13D shows a pupil intensitydistribution of the linearly polarized light of +45 degree obliquedirection.

On this occasion, suppose that the number N of the mirror elements ofthe spatial light modulator 3 is 64×64=4,096, and the number of thepupil plane sections is 25×25=625. The surface light sources P11 a andP11 b each occupy 30 sections on the pupil plane, the surface lightsources P14 a and P14 b each occupy 12 sections on the pupil plane, andthe surface light sources P12 a and P12 b, and P13 a and P13 b eachoccupy 4 sections on the pupil plane.

Then, because the surface light sources P12 a and P12 b, and P13 a andP13 b are supposed to have twice the light intensity of the surfacelight sources P11 a and P11 b, and P14 a and P14 b, the light from4,096/116=35 mirror elements reaches one section in the surface lightsources P11 a and P11 b, and P14 a and P14 b. Further, the light from 70mirror elements reaches one section in the surface light sources P12 aand P12 b, and P13 a and P13 b. Further, the light from 36 mirrorelements, i.e., the remainder of 4,096/116, is guided to the outside ofthe effective region of the optical system, and thus does not contributeto the formation of the pupil intensity distribution.

Thus, the number Nz of mirror elements necessary for generating the Zdirection linearly polarized light is 35×30×2=2,100; the number Nx ofmirror elements necessary for generating the X direction linearlypolarized light is 35×12×2=840; the number N−45 of mirror elementsnecessary for generating the linearly polarized light of −45 degreeoblique direction is 70×4×2=560, and the number N+45 of mirror elementsnecessary for generating the linearly polarized light of +45 degreeoblique direction is 70×4×2=560.

Therefore, the control system CR virtually divides the plurality ofmirror elements of the spatial light modulator 3 into the first mirrorelement group S01 composed of 2,100 mirror elements, the second mirrorelement group S02 composed of 560 mirror elements, the third mirrorelement group S03 composed of 560 mirror elements, and the fourth mirrorelement group S04 composed of 840 mirror elements, so as to set thepartial regions R01 to R04 in which the mirror element groups S01 to S04are positioned respectively, and the partial regions R1 to R14corresponding respectively to the partial regions R01 to R04. Then, thecontrol system CR drives the optical rotation members 51 and 52 of thepolarization unit 5 to position the optical rotation member 51 into thepartial regions R12 and R13, and position the optical rotation member 52into the partial regions R13 and R14.

Further, the control system CR drives and sets the mirror elements 3 aof the first mirror element group S01 and fourth mirror element groupS04 such that the light from the first mirror element group S01 isdirected toward the surface light sources P11 a and P11 b, and the lightfrom the fourth mirror element group S04 is directed toward the surfacelight sources P14 a and P14 b. Then, the control system CR drives andsets the mirror elements 3 a of the second mirror element group S02 andthird mirror element group S03 such that the light from the secondmirror element group S02 is directed toward the surface light sourcesP12 a and P12 b, and the light from the third mirror element group S03is directed toward the surface light sources P13 a and P13 b.

On this occasion, the control system CR sets the mirror elements 3 asuch that the light from two mirror elements 3 a of the second mirrorelement group S02 is directed toward one section in the surface lightsources P12 a and P12 b, and the light from two mirror elements 3 a ofthe third mirror element group S03 is directed toward one section in thesurface light sources P13 a and P13 b. By causing the control system CRto control the spatial light modulator 3 and polarization unit 5 asabove, it is possible to form the pupil intensity distribution 21 c ofFIG. 12.

The above embodiment shows an example of causing the pair of opticalrotation members 51 and 52 to affect the incident light beam F1.However, without being limited to this, it is also possible to withdraw,for example, the optical rotation member 51 from the optical path andcause the optical rotation member 52 alone to affect the incident lightbeam F1. On this occasion, by the edge 52 b of the optical rotationmember 52, the incident light beam F1 is divided into two partial lightbeams. One partial light beam (corresponding to the partial light beamsF11+F12 of FIG. 6) is guided to the pupil regions R11 a and R11 b on theillumination pupil plane, as shown in FIG. 14, without passing throughthe optical rotation member 52, to form the surface light sources P11 aand P11 b of the Z direction linearly polarized light.

The other partial light beam (corresponding to the partial light beamsF13+F14 of FIG. 6) is guided to the pupil regions R14 a and R14 b on theillumination pupil plane via the optical rotation member 52, to form thesurface light sources P14 a and P14 b of the X direction linearlypolarized light. In this manner, in the illumination pupil justdownstream from the micro fly's eye lens 7, there is formed, forexample, a four pole-shaped pupil intensity distribution 24 in acircumferential direction polarization state composed of four circularsubstantial surface light sources P11 a and P11 b, and P14 a and P14 b.By moving the optical rotation member 52 in the X direction, it ispossible to relatively change the light intensity between the foursurface light sources constituting the four pole-shaped pupil intensitydistribution 24 while maintaining the circumferential directionpolarization state.

The above embodiment shows an example of forming the eight pole-shapedpupil intensity distribution 21 a in the circumferential directionpolarization state. However, without being limited to this, by onlycontrolling the spatial light modulator 3 according to a command fromthe control system CR, as shown in FIG. 15, it is also possible to forma nine pole-shaped pupil intensity distribution 25 which is obtained byadding a central pole P1 c to the eight pole-shaped pupil intensitydistribution 21 a. In the example shown in FIG. 15, part of the firstpartial light beam F11, part of the second partial light beam F12, partof the third partial light beam F13, and part of the fourth partiallight beam F14 are guided to, for example, a circular pupil region R1 caround the optical axis AX on the illumination pupil plane, to form thesurface light source P1 c in a substantial non-polarization state inwhich four linear polarization components coexist.

Alternatively, as shown in FIG. 16, it is also possible to form the ninepole-shaped pupil intensity distribution 25 by providing thepolarization unit 5 additionally with a depolarization element 53insertable to and removable from the illumination optical path. Thedepolarization element 53 is insertable and removable in a positionoptically conjugate with the arrangement plane of the spatial lightmodulator 3 or in its vicinity. The depolarization element 53 can beconstructed of a first deflection prism (wedge-like plate) which is madeof a birefringent material such as crystal and whose thickness varieswith the passage position of light beam, and a second deflection prismwhich is made of a non-birefringent material such as silica glass andfunctions as a correcting plate for restoring the light beams deflectedby the deflection effect of the first deflection prism to the originalstate, arranged in this order from the incident side of the light.Further, reference can also be made to a depolarizer disclosed in U.S.Pat. No. 7,423,731.

In the example of FIG. 16, among the incident light beam F1, the lightbeam at the +X direction side of the edge 51 b of the optical rotationmember 51 is divided into the first partial light beam F11 travellingtoward the relay optical system 6 without passing through thedepolarization element 53, and a fifth partial light beam F15 travellingtoward the relay optical system 6 via the depolarization element 53.

The first partial light beam F11 is guided to the pupil regions R11 aand R11 b shown in FIG. 15 without passing through the optical rotationmembers 51 and 52 and depolarization element 53, to form the surfacelight sources P11 a and P11 b of the Z direction linearly polarizedlight. The fifth partial light beam F15 is guided to the pupil region R1c shown in FIG. 15 only via the depolarization element 53 withoutpassing through the optical rotation members 51 and 52, to form thesurface light source P1 c in the non-polarization state. Further, in theexample of FIG. 16, by withdrawing the optical rotation member 51 fromthe optical path and causing the optical rotation member 52 anddepolarization element 53 to affect the incident light beam F1, as shownin FIG. 17, it is also possible to form a five pole-shaped pupilintensity distribution 26 obtained by adding the central pole P1 c inthe non-polarization state to the four pole-shaped pupil intensitydistribution 24.

The above embodiment shows an example of the polarization unit 5including the optical rotation members 51 and 52 being movable in the Xdirection and having the pairs of edges 51 a and 51 b and edges 52 a and52 b extending in the Y direction. In this case, although it is possibleto change the ratio between the cross-sectional area of the firstpartial light beam F11, the cross-sectional area of the second partiallight beam F12, the cross-sectional area of the third partial light beamF13, and the cross-sectional area of the fourth partial light beam F14,it is not possible to control the cross-sectional area of each partiallight beam in a mutually independent manner. FIG. 18 shows an example ofusing a polarization unit 5A constructed from a pair of optical rotationmembers 51A and 52A having a trapezoidal outer shape (contour) tocontrol the cross-sectional area of each partial light beam in amutually independent manner.

In the example shown in FIG. 18, the optical rotation member 51A has afirst edge 51Aa extending in a direction obliquely intersecting the Ydirection along which there extends one pair of sides of the rectangularcross section of the incident light beam F1, and a second edge 51Abextending in a direction intersecting the Y direction obliquely butdiffering from the direction along which the first edge 51Aa extends.Likewise, the optical rotation member 52A arranged adjacently on theemission side of the optical rotation member 51A has a first edge 52Aaextending in a direction intersecting the Y direction obliquely, and asecond edge 52Ab extending in a direction intersecting the Y directionobliquely but differing from the direction along which the first edge52Aa extends. The optical rotation members 51A and 52A are movable inthe X direction and in the Y directions, and consequently, movabletwo-dimensionally along a cross section (X-Y plane) of the incidentlight beam F1.

In the example shown in FIG. 18, the optical rotation members 51A and52A having the edges 51Aa and 51Ab, and 52Aa and 52Ab extending in thedirections obliquely intersecting the Y direction along which thereextends the one pair of sides of the cross section of the incident lightbeam F1, are moved two-dimensionally along the cross section of theincident light beam F1. By doing so, it is possible to control thecross-sectional area of the first partial light beam F11, thecross-sectional area of the second partial light beam F12, thecross-sectional area of the third partial light beam F13, and thecross-sectional area of the fourth partial light beam F14, in a mutuallyindependent manner. As a result, it is possible to further raise thedegree of freedom with respect to relative change of the lightintensities of respective surface light sources constituting, forexample, the eight pole-shaped pupil intensity distribution 21 a.According to this configuration, even if the light intensitydistribution of the incident light beam F1 is not uniform and changeswith the passage of time, it is still possible to maintain a desiredrelative relation between the light intensities of the respectivesurface light sources constituting, for example, the eight pole-shapedpupil intensity distribution 21 a.

Further, FIG. 18 shows an example that the pair of optical rotationmembers 51A and 52A constituting the polarization unit 5A both have atrapezoidal outer shape. However, without being limited to this, it ispossible to adopt various forms for the outer shape of the pair ofoptical rotation members constituting the polarization unit. Forexample, as shown in FIG. 19, it is also possible to adopt amodification in which it is used a polarization unit 5B including anoptical rotation member 52B instead of the optical rotation member 52Aof FIG. 18, the optical rotation member 52B having a first edge 52Baextending in the Y direction, and a second edge 52Bb extending in adirection obliquely intersecting the Y direction. Further, as shown inFIG. 20, it is also possible to adopt another modification in which itis used a polarization unit 5C including an optical rotation member 51Binstead of the optical rotation member 51A of FIG. 19, the opticalrotation member 51B having a first edge 51Ba extending in the Ydirection, and a second edge 51Bb extending in a direction obliquelyintersecting the Y direction.

Although, in the above embodiment, the parallel light beam along theoptical axis AX is supposed to come into the polarization unit 5, thereis in reality also some light which comes into the polarization unit 5obliquely to the optical axis AX (which does not vertically comes intothe optical rotation members 51 and 52). In this case, the linearlypolarized light vertically coming into the optical rotation member 51 or52 formed of crystal maintains its linear polarization state while onlychanging its polarization direction, but the linearly polarized lightobliquely coming into the optical rotation member 51 or 52 iselliptically polarized and then emitted therefrom. This is because thelight obliquely coming into the optical rotation member 51 or 52propagates obliquely to the crystalline optic axis of crystal, andtherefore is imparted with a phase difference.

Hence, as shown in FIG. 21, it is also possible to adopt aconfigurational example of using, for example, an optical rotationmember 52C, instead of the optical rotation member 52, which includes afirst optical rotation member 52R formed of a clockwise optical rotationmember (clockwise-rotation crystal), and a second optical rotationmember 52L formed of a counterclockwise optical rotation member(counterclockwise-rotation crystal) and arranged adjacently on theemission side of the first optical rotation member 52R. In the exampleof FIG. 21, the longitudinally polarized light vertically coming intothe first optical rotation member 52R is first transformed into anobliquely polarized light, then transformed by the second opticalrotation member 52L into a transversely polarized light, and finallyemitted therefrom. The longitudinally polarized light obliquely cominginto the first optical rotation member 52R is first transformed into anelliptically polarized light, then transformed by the second opticalrotation member 52L into a transversely polarized light, and finallyemitted therefrom. That is, the light obliquely coming into the opticalrotation member 52C is also emitted from the optical rotation member 52Cin the same polarization state as the emission light resulting from thelight vertically coming into the optical rotation member 52C.

Further, instead of the configuration of FIG. 21 (or in addition to theconfiguration of FIG. 21), as shown in FIG. 22, it is also possible toadopt a configuration of arranging a phase difference imparting member11 at the position of the pupil plane 4 c of the relay optical system 4,which is an optical Fourier transform plane of the arrangement plane ofthe spatial light modulator 3, or in its vicinity, to impart theincident light with phase differences which are different based on theincident position. In the configuration of FIG. 22, an incident positionfor the phase difference imparting member 11 is converted into anincident angle for the polarization unit 5 by the effect of the backside lens group 4 b of the relay optical system 4.

As described above, an amount of elliptical polarization changesaccording to the incident angle to the optical rotation members 51 and52. However, in the configuration of FIG. 22, because the phasedifference imparting member 11 imparts in advance a phase difference toset off (or compensate) the change of the amount of the ellipticalpolarization caused at the polarization unit 5 in accordance with theincident angle for the polarization unit 5. Thus, the light obliquelycoming into the polarization unit 5 is emitted from the polarizationunit 5 in the same polarization state as the emission light resultingfrom the vertically incident light. Further, it is also possible toadopt a configuration of arranging the phase difference imparting member11 on an optical Fourier transform plane of the arrangement plane of thespatial light modulator 3 in the optical path on the downstream side ofthe polarization unit 5.

Further, as shown in FIGS. 23A to 23C, it is also possible to adopt aconfiguration of obtaining, for example, a polarization rotator 52D,instead of the optical rotation member 52, by combining a ½ wave plate52D1 with an optic axis in a first direction (the Y direction here)within a plane (within the X-Y plane) orthogonal to the optical axis AXof the illumination optical system, and a ½ wave plate 52D2 with anoptic axis in a second direction within a plane (within the X-Y plane)orthogonal to the optical axis AX of the illumination optical system.Here, FIG. 23B is an X-Y plane view of the ½ wave plate 52D1, while FIG.23C is an X-Y plane view of the ½ wave plate 52D2. Just as shown in FIG.23C, the second direction, i.e., the direction along the optic axis ofthe ½ wave plate 52D2, is a direction obtained by rotating the firstdirection by an angle θ.

Now, a Mueller matrix will be used to explain the effects of the ½ waveplate 52D1 and the ½ wave plate 52D2. The Mueller matrix is disclosedin, for example, the document “Edited by Michael Bass et al.: HANDBOOKOF OPTICS, Chapter 22: Polarimetry, pp. 22-8 to 22-14, by McGRAW-HILL,Inc., 1995, in the United States”.

The following expression 1 denotes the Mueller matrix expressing thepolarization effect of the ½ wave plate 52D1, while the followingexpression 2 denotes the Mueller matrix expressing the polarizationeffect of the ½ wave plate 52D2.

$\begin{matrix}\left\lbrack {{Expressions}\mspace{14mu} I} \right\rbrack & \; \\\begin{pmatrix}1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & {- 1} & 0 \\0 & 0 & 0 & {- 1}\end{pmatrix} & (1) \\\begin{pmatrix}1 & 0 & 0 & 0 \\0 & {\cos\mspace{11mu} 4\;\theta} & {\sin\mspace{11mu} 4\;\theta} & 0 \\0 & {\sin\mspace{11mu} 4\;\theta} & {{- \cos}\mspace{11mu} 4\;\theta} & 0 \\0 & 0 & 0 & {- 1}\end{pmatrix} & (2)\end{matrix}$

Then, the following expression 3 denotes the Mueller matrix expressingthe polarization effect of the optical element obtained by combiningthose ½ wave plates 52D1 and 52D2.

$\begin{matrix}\left\lbrack {{Expression}\mspace{14mu}{II}} \right\rbrack & \; \\{{\begin{pmatrix}1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & {- 1} & 0 \\0 & 0 & 0 & {- 1}\end{pmatrix}\begin{pmatrix}1 & 0 & 0 & 0 \\0 & {\cos\mspace{11mu} 4\;\theta} & {\sin\mspace{11mu} 4\;\theta} & 0 \\0 & {\sin\mspace{11mu} 4\;\theta} & {{- \cos}\mspace{11mu} 4\;\theta} & 0 \\0 & 0 & 0 & {- 1}\end{pmatrix}} = \begin{pmatrix}1 & 0 & 0 & 0 \\0 & {\cos\mspace{11mu} 4\;\theta} & {\sin\mspace{11mu} 4\;\theta} & 0 \\0 & {{- \sin}\mspace{11mu} 4\;\theta} & {\cos\mspace{11mu} 4\;\theta} & 0 \\0 & 0 & 0 & 1\end{pmatrix}} & (3)\end{matrix}$

The right-hand side of the expression 3 is the same as the Muellermatrix expressing the polarization effect of an optical rotator (azimuthrotator). That is, the optical element obtained by combining the ½ waveplates 52D1 and 52D2 is equivalent to an optical rotator (opticalrotation member). Further, by setting 45 degrees (θ=45 degrees) for thedirection of the optic axis of the ½ wave plate 52D2 relative to thedirection of the optic axis of the ½ wave plate 52D1, the opticalelement becomes an optical rotator rotating the polarization directionof a linearly polarized incident light by 90 degrees and, by changingthe setting angle θ, it is possible to rotate the polarization directionof the linearly polarized incident light by any angle. In themodification of FIGS. 23A to 23C, it is possible to combine the ½ waveplates 52D1 and 52D2 into a layered body and rotate the one bodyintegrally, and it is also possible to separate the ½ wave plate 52D1from the ½ wave plate 52D2 and rotate the two separated membersrelatively.

The modification of FIGS. 23A to 23C does not use an optical rotatorwhose optic axis is oriented along the light incident direction, butuses the wave plates whose optic axes are oriented within a plane almostorthogonal to the light incident direction. Thus, it is possible tosecure a wide range of allowable incident angle within which a desiredpolarization modulation can be maintained. Therefore, even if there isan angular distribution in the light beam coming into the polarizationunit 5 (polarization rotator 52D), it is still possible to exert apolarization rotation effect on all light beams in the angulardistribution without causing change of the degree of orvalization(degree of elliptical polarization). Consequently, it is easy to seteach surface light source constituting the pupil intensity distributionto a desired polarization state.

In the above embodiment, it is supposed to arrange the optical rotationmembers 51 and 52 adjacent to each other in a position opticallyconjugate with the arrangement plane of the spatial light modulator 3.In reality, however, it is not possible to arrange the pair of opticalrotation members 51 and 52 in the same position. Therefore, inparticular as shown in FIG. 24, it is possible to arrange the pair ofoptical rotation members 51 and 52 across a position 3 e opticallyconjugate with an arrangement plane 3 d of the spatial light modulator3. The conjugate position 3 e is defined as the point at which theoptical axis AX of the relay optical system 4 intersects a plane 3 foptically conjugate with the arrangement plane 3 d.

Similar to the arrangement plane 3 d, the plane 3 f optically conjugatewith the arrangement plane 3 d is inclined with respect to a planeorthogonal to the optical axis AX. The inclination of the plane 3 f withrespect to the plane orthogonal to the optical axis AX decreases as theabsolute value of the image forming magnification of the relay opticalsystem 4 increases. The optical rotation member 51 is arranged along aplane PLN1 orthogonal to the optical axis AX in a position just a littleupstream from the position 3 e, while the optical rotation member 52 isarranged along a plane PLN2 orthogonal to the optical axis AX in aposition just a little downstream from the position 3 e. On thisoccasion, it is possible to respectively move the pair of opticalrotation members 51 and 52 along the plane PLN and the plane PLN2 or, asshown in FIG. 25 for example, to move the pair of optical rotationmembers 51 and 52 along a plane parallel to the plane 3 f conjugate withthe arrangement plane 3 d of the spatial light modulator 3.

Further, in the above embodiment, as shown in FIG. 26 for example, it isalso possible to arrange the pair of optical rotation members 51 and 52along a plane parallel to the plane 3 f conjugate with the arrangementplane 3 d of the spatial light modulator 3, and move the pair of opticalrotation members 51 and 52 along the plane parallel to the conjugateplane 3 f. On this occasion, the pair of optical rotation members 51 and52 may be arranged adjacent to each other in a direction along theillumination optical path, and may be arranged across the conjugateplane 3 f.

In the above embodiment, the pair of optical rotation members 51 and 52are arranged adjacent to each other to constitute the polarization unit5. However, without being limited to this, it is also possible to adopta configuration in which a relay optical system is arranged between theoptical rotation members 51 and 52 such that the optical rotation member51 and the optical rotation member 52 are optically conjugate with eachother.

In the above embodiment, the optical rotation members 51 and 52 areformed of crystal. However, without being limited to this, it is alsopossible to use other suitable optical materials having optical rotationproperty to form the optical rotation members.

In the above embodiment, the polarization unit 5 is constructed from thepair of optical rotation members (optical elements) 51 and 52 formed ofan optical material having optical rotation property. However, withoutbeing limited to this, it is also possible to adopt variousconfigurations for the outer shape, number, arrangement, opticalproperty, etc. of the optical elements constituting the polarizationunit. For example, it is possible to construct the polarization unit byusing a wave plate changing the incident light into the light in apredetermined polarization state, or construct the polarization unit byusing a polarizer selecting light in a predetermined polarization statefrom the incident light to emit the selected light. Further, if apolarizer is used to construct the polarization unit, then, for example,the light having a non-polarization state is made incident.

Referring to FIGS. 27 and 28, an explanation will be given about anothermodification using a pair of wave plates to construct a polarizationunit. Referring to FIG. 27, a polarization unit 5D includes a ½ waveplate 54 having the same outer shape as the optical rotation member 51of the polarization unit 5 and being arranged in the same manner as theoptical rotation member 51, and a ½ wave plate 55 having the same outershape as the optical rotation member 52 and being arranged in the samemanner as the optical rotation member 52. That is, the ½ wave plates 54and 55 respectively have a pair of edges 54 a and 54 b and a pair ofedges 55 a and 55 b extending in the Y direction.

The ½ wave plate 54 has an optic axis in a direction obtained byrotating the Y direction clockwise by +22.5 degrees in its standardstate and, consequently, has the same polarization transformationproperty as the optical rotation member 51. The ½ wave plate 55 has anoptic axis in a direction obtained by rotating the Y direction clockwiseby +45 degrees in its standard state and, consequently, has the samepolarization transformation property as the optical rotation member 52.The ½ wave plates 54 and 55 are movable in the X direction and in the Ydirection and, consequently, movable two-dimensionally along a crosssection of the incident light beam F1 (the X-Y plane). Further, the ½wave plates 54 and 55 are rotatable along the cross section of theincident light beam F1 (the X-Y plane) and, consequently, able to adjustthe directions of the optic axes.

The polarization unit 5D constructed by using the pair of ½ wave plates54 and 55 fulfills the same function as the polarization unit 5constructed from the pair of optical rotation members 51 and 52.Further, different from the polarization unit 5, the polarization unit5D can adjust the polarization state of each surface light sourceconstituting, for example, the eight pole-shaped pupil intensitydistribution 21 a by changing the directions of the optic axes of the ½wave plates 54 and 55.

Referring to FIG. 28, a polarization unit 5E includes a ½ wave plate 54Ahaving the same outer shape as the optical rotation member 51A of thepolarization unit 5A and being arranged in the same manner as theoptical rotation member 51A, and a ½ wave plate 55A having the sameouter shape as the optical rotation member 52A and being arranged in thesame manner as the optical rotation member 52A. That is, the ½ waveplates 54A and 55A respectively have a pair of edges 54Aa and 54Ab and apair of edges 55Aa and 55Ab extending in a direction obliquelyintersecting the Y direction along which the one pair of sides of thecross section of the incident light beam F1 extend.

The ½ wave plate 54A has an optic axis in a direction obtained byrotating the Y direction clockwise by +22.5 degrees in its standardstate and, consequently, has the same polarization transformationproperty as the optical rotation member 51A. The ½ wave plate 55A has anoptic axis in a direction obtained by rotating the Y direction clockwiseby +45 degrees in its standard state and, consequently, has the samepolarization transformation property as the optical rotation member 52A.The ½ wave plates 54A and 55A are movable in the X direction and in theY direction and, consequently, movable two-dimensionally along the crosssection of the incident light beam F1 (the X-Y plane). Further, the ½wave plates 54A and 55A are rotatable along the cross section of theincident light beam F1 (the X-Y plane) and, consequently, able to adjustthe directions of the optic axes.

The polarization unit 5E constructed by using the pair of ½ wave plates54A and 55A fulfills the same function as the polarization unit 5Aconstructed from the pair of optical rotation members 51A and 52A.Further, different from the polarization unit 5A, the polarization unit5E can adjust the polarization state of each surface light sourceconstituting, for example, the eight pole-shaped pupil intensitydistribution 21 a by changing the directions of the optic axes of the ½wave plates 54A and 55A.

In the above embodiment, the polarization unit 5 is arranged in aposition conjugate with the arrangement plane of the spatial lightmodulator 3 for the plurality of mirror elements 3 a in the optical pathon the illumination objective surface side of the spatial lightmodulator 3. However, without being limited to this, it is also possibleto arrange the polarization unit 5 in a position conjugate with thearrangement plane of the spatial light modulator 3 for the plurality ofmirror elements 3 a in the optical path on the light source side of thespatial light modulator 3.

Referring to FIG. 29, an explanation will be given about still anothermodification arranging the polarization unit 5 in a position conjugatewith the arrangement plane of the spatial light modulator 3 for theplurality of mirror elements 3 a in the optical path on the light sourceside of the spatial light modulator 3. FIG. 29 shows an optical pathfrom a light amount uniformization element (a light amount equalizationelement) 12 receiving the light from the light source 1, to the pupilplane 4 c, of the relay optical system 4, which is an optical Fouriertransform plane of the arrangement plane of the spatial light modulator3. Regarding other configurations than the optical path shown in FIG.29, reference can be made to FIG. 2. Further, the members havingidentical or similar functions to those of the members in theaforementioned embodiment and modifications are denoted by the referencenumerals same as those of the members in the aforementioned embodimentand modifications.

In FIG. 29, the light from an unshown light source enters the lightamount uniformization element 12 to undergo wavefront division. Eachlight beam resulted from the wavefront division by the light amountuniformization element 12 is emitted from the light amountuniformization element 12 at a predetermined divergence angle, andpasses through a condenser optical system 13 having a front focalposition on an arrangement plane of the light amount uniformizationelement 12, so as to illuminate a back focal plane 12 b of the condenseroptical system 13 in a superimposed (overlaid) manner. Then, anillumination field with a substantively uniform illuminance distributionis formed on the plane 12 b and, an image of the illumination field isformed on the spatial light modulator 3 via a relay optical system 40.

That is, the relay optical system 40 makes the plane 12 b and thespatial light modulator 3 optically conjugate with each other. Further,it is appropriate to say that the relay optical system 40 forms theposition 3 e conjugate with the arrangement plane 3 d of the spatiallight modulator 3 for the plurality of mirror elements 3 a in theoptical path on the light source side of the spatial light modulator 3.Here, the position 3 e optically conjugate with the arrangement plane 3d of the spatial light modulator 3 is located on the plane 12 b wherethe illumination field is formed by the light amount uniformizationelement 12 and the condenser optical system 13. Further, as the lightamount uniformization element 12, it is possible to use, for example, awavefront division element such as a refracting array element such as afly's eye lens or the like, reflecting array element, diffracting arrayelement, etc.

In the example of FIG. 29, it is possible to arrange the pair of opticalrotation members 51 and 52 of the polarization unit 5 in the position 3e conjugate with the arrangement plane 3 d of the spatial lightmodulator 3, to supply light beams in different polarization states toeach of the mirror element groups of the plurality of mirror elements 3a of the spatial light modulator 3. Then, when setting each surfacelight source constituting the pupil intensity distribution via each ofthe plurality of mirror element groups of the spatial light modulator 3,because it is possible to secure a desired polarization state for eachlight beam to be supplied to the respective mirror element groups, it ispossible to set a desired polarization state for each surface lightsource. In the example of FIG. 29, it is also possible to reduce theadverse influence of defocus at the edges of the polarization members ofthe polarization unit 5 (the optical rotation members 51 and 52).Further, it is also possible to combine the example of FIG. 29 with theconfigurations shown in the aforementioned embodiment and modifications.

Further, in the above embodiment and modifications, the polarizationunit 5 is arranged in a position conjugate with the arrangement plane ofthe spatial light modulator 3 for the plurality of mirror elements 3 a.However, it is also possible to use the polarization unit 5 incombination with a polarization unit 14 arranged in an optical Fouriertransform plane of the arrangement plane of the spatial light modulator3 for the plurality of mirror elements 3 a to transform the linearlypolarized incident light into a circumferential direction linearlypolarized light or a radial direction linearly polarized light. Thiswill be explained below with reference to FIGS. 30 to 32.

FIG. 30 shows an optical path from the light source 1 to the micro fly'seye lens 7. Regarding other configurations than the optical path shownin FIG. 30, reference can be made to FIG. 2. Further, the members havingidentical or similar functions to those of the members in theaforementioned embodiment and modifications are denoted by referencenumerals same as those of the members in the aforementioned embodimentand modifications. In FIG. 30, the configuration is different from theexample shown in FIG. 2 in that the polarization unit 14 is arranged inthe pupil plane 4 c of the relay optical system 4, i.e., an opticalFourier transform plane of the arrangement plane of the spatial lightmodulator 3, to transform the linearly polarized incident light into acircumferential direction linearly polarized light or a radial directionlinearly polarized light.

As shown in FIG. 31, the polarization unit 14 has a circular (orannular) outer shape about the optical axis AX, and has eight divisionregions 14 a to 14 h obtained by dividing the circle into eight partsalong its circumferential direction. Further, the polarization unit 14is formed of a crystalline material, such as crystal, which is anoptical material having optical rotation property. With the polarizationunit 14 being positioned in the illumination optical path, the incidentsurface and emission surface of the polarization unit 14 are orthogonalto the optical axis AX, and its crystalline optic axis is substantiallyconsistent with the direction along the optical axis AX (that is,substantially consistent with the Z direction which is the propagationdirection of the incident light).

Here, a thickness of the division regions 14 a and 14 e in the opticalaxis AX direction is set such that, for example, if a linearly polarizedlight having the polarization direction in the Y direction comes intothe polarization unit 14, then there is emitted a linearly polarizedlight having the polarization direction in a direction obtained byrotating, about the Z-axis, the Y direction by +90 degrees+180×n degrees(n is an integer), i.e., in X direction. Further, a thickness of thedivision regions 14 b and 14 f in the optical axis AX direction is setsuch that, for example, if a linearly polarized light having thepolarization direction in the Y direction comes into the polarizationunit 14, then there is emitted a linearly polarized light having thepolarization direction in a direction obtained by rotating, about theZ-axis, the Y direction by +135 degrees+180×n degrees (n is an integer),i.e., in a direction obtained by rotating, about the Z-axis, the Ydirection by −45 degrees.

Further, a thickness of the division regions 14 c and 14 g in theoptical axis AX direction is set such that, for example, if a linearlypolarized light with the polarization direction in the Y direction comesinto the polarization unit 14, then there is emitted a linearlypolarized light having the polarization direction in a directionobtained by rotating, about the Z-axis, the Y direction by +180degrees+180×n degrees (n is an integer), i.e., in the Y direction. Then,a thickness of the division regions 14 d and 14 h in the optical axis AXdirection is set such that, for example, if a linearly polarized lightwith the polarization direction in the Y direction comes into thepolarization unit 14, then there is emitted a linearly polarized lighthaving the polarization direction in a direction obtained by rotating,about the Z-axis, the Y direction by +45 degrees+180×n degrees (n is aninteger), i.e., in a direction obtained by rotating, about the Z-axis,the Y direction by +45 degrees.

Returning to FIG. 30, if the light reaching the spatial light modulator3 from the light source 1 is a linearly polarized light having thepolarization direction in the Y direction, and the inclinations of theplurality of mirror elements 3 a of the spatial light modulator 3 areset so as to form a eight pole-shaped light intensity distribution onthe pupil plane 4 c, then via the polarization unit 14, the lightintensity distribution has a circumferential direction linearpolarization state about the optical axis AX. Then, if the polarizationunit 5 is not located in the optical path of the illumination opticalsystem, as shown in FIG. 9A, the eight pole-shaped light intensitydistribution in the circumferential direction linear polarization stateis also formed on the illumination pupil plane just downstream from themicro fly's eye lens 7.

Here, consider a case that the polarization unit 5 is an opticalrotation member which rotates the polarization direction of a linearlypolarized incident light about the optical axis by +90 degrees+180×ndegrees (n is an integer). If the polarization unit 5 is positioned in aregion conjugate with the partial region where it is positioned theplurality of mirror elements 3 a for forming the surface light sourcesP12 a and P12 b, and P13 a and P13 b in the eight pole-shaped lightintensity distribution formed on the illumination pupil plane justdownstream from the micro fly's eye lens 7, among the plurality ofmirror elements 3 a of the spatial light modulator 3, then as shown inFIG. 9B, it is possible to obtain such a polarization state that thesurface light sources P11 a and P11 b, and P14 a and P14 b, which arethe upper, lower, left and right poles, are the linearly polarized lighthaving the polarization direction in the circumferential direction,while the surface light sources P12 a and P12 b, and P13 a and P13 b,which are the poles of ±45 degree oblique directions, are the linearlypolarized light having the polarization direction in the radialdirection.

In this manner, it is possible to acquire a high degree of freedom inchanging the polarization state by combining the polarization unit 14forming the circumferential direction linearly polarized light on theillumination pupil plane, and the polarization unit 5 arranged in theposition conjugate with the arrangement plane of the spatial lightmodulator 3 for the plurality of mirror elements 3 a.

Further, it is also possible to combine the modification shown in FIGS.30 and 31, and any one of the embodiment and modifications describedabove. Further, as shown in FIG. 32, it is also possible to adopt aconfiguration of arranging the polarization unit both in the conjugateposition in the optical path on the illumination objective surface sideof the spatial light modulator 3, and in the conjugate position in theoptical path on the light source side of the spatial light modulator 3,by combining the embodiment shown in FIG. 2 and the modification shownin FIG. 29.

In the embodiment described above, the spatial light modulator, in whichthe directions (angles, inclinations) of the plurality of reflectingsurfaces arranged two-dimensionally can be individually controlled, isused as the spatial light modulator having the plurality of mirrorelements arranged two-dimensionally and controlled individually.However, there is no limitation thereto. For example, it is alsopossible to use a spatial light modulator in which the heights(positions) of a plurality of reflecting surfaces arrangedtwo-dimensionally can be individually controlled. As for the spatiallight modulator as described above, it is possible to use, for example,spatial light modulators disclosed in U.S. Pat. No. 5,312,513 and FIG.1d of U.S. Pat. No. 6,885,493. In the case of those spatial lightmodulators, the action or function, which is the same as or equivalentto that of the diffraction surface, can be given to the incident lightby forming the two-dimensional height distribution. The spatial lightmodulator described above, which has the plurality of reflectingsurfaces arranged two-dimensionally, may be modified in accordance withthe disclosure of, for example, U.S. Pat. No. 6,891,655 and UnitedStates Patent Application Publication No. 2005/0095749.

In the embodiment described above, the spatial light modulator 3 isprovided with the plurality of mirror elements 3 a arrangedtwo-dimensionally in the predetermined plane. However, there is nolimitation thereto. It is also possible to use a transmission typespatial light modulator provided with a plurality of transmissionoptical elements arranged in a predetermined plane and controlledindividually.

In the embodiment described above, a variable pattern forming apparatus,which forms a predetermined pattern on the basis of predeterminedelectronic data, can be used in place of the mask. As for the variablepattern forming apparatus, for example, it is possible to use a spatiallight modulating element including a plurality of reflecting elementsdriven on the basis of predetermined electronic data. An exposureapparatus, which uses the spatial light modulating element, isdisclosed, for example, in United States Patent Application PublicationNo. 2007/0296936. Other than the reflection type spatial light modulatorof the non-light emission type as described above, it is also allowableto use a transmission type spatial light modulator, and it is alsoallowable to use an image display element of the self-light emissiontype.

In the aforementioned embodiment, the optical rotation members 51 and 52rotate the polarization direction of a linearly polarized incident lightby 45 degrees and 90 degrees, respectively. However, the rotation anglefor the polarization direction is not limited to 45 degrees or 90degrees.

The optical rotation member 51 may rotate the polarization direction ofa linearly polarized incident light by any rotation angle of 45degrees+180×n degrees (n is an integer) such as 255 degrees, 405degrees, etc. The optical rotation member 52 may rotate the polarizationdirection of a linearly polarized incident light by any rotation angleof 90 degrees+180×n degrees (n is an integer) such as 270 degrees, 450degrees, etc. That is, the optical rotation member 51 may rotate thepolarization direction of a linearly polarized incident light by anyrotation angle of j degrees+180×n degrees (j is a real number and n isan integer), while the optical rotation member 52 may rotate thepolarization direction of a linearly polarized incident light by anyrotation angle of k degrees+180×n degrees (k is a real number and n isan integer).

Further, as described above, any number of optical rotation members orphase members (typically wave plates) may be used as movablepolarization rotation members constituting the polarization unit 5 and,as shown in FIGS. 33A and 33B for example, it is possible to constructpolarization units 5F and 5G with three movable polarization rotationmembers, respectively.

In FIG. 33A, the polarization unit 5F is constructed from threepolarization rotation members 51F, 52F and 56F movable in the Xdirection of the figure. Here, each of the polarization rotation members51F, 52F and 56F rotates the polarization direction of a linearlypolarized incident light by 135 degrees. Those polarization rotationmembers 51F, 52F and 56F may either be constructed of optical rotationmembers or wave plates, or be the aforementioned wave plates shown inFIGS. 23A to 23C. In FIG. 33A, if the linearly polarized light cominginto the polarization unit 5F is a Y direction linearly polarized light,then the first partial light beam F11 does not pass through any of thepolarization rotation members 51F, 52F and 56F, and remains the Ydirection linearly polarized light as it is at a position justdownstream from the polarization unit 5F. The second partial light beamF12 passes through the polarization rotation member 51F, and is alinearly polarized light of +135 degree oblique direction at a positionjust downstream from the polarization unit 5F. The third partial lightbeam F13 passes through the polarization rotation members 51F and 52F,and is a linearly polarized light of +270 degree oblique direction (a Xdirection linearly polarized light) at a position just downstream fromthe polarization unit 5F. The fourth partial light beam F14 passesthrough the polarization rotation members 51F, 52F and 56F, and is alinearly polarized light of +405 degree oblique direction at a positionjust downstream from the polarization unit 5F.

Further, in FIG. 33B, the polarization unit 5G is constructed from threepolarization rotation members 51G, 52G and 56G movable in the Xdirection of the figure. Here, each of the polarization rotation members51G and 56G rotates the polarization direction of a linearly polarizedincident light by 90 degrees, while the polarization rotation member 52Grotates the polarization direction of a linearly polarized incidentlight by 135 degrees. Those polarization rotation members 51G, 52G and56G may either be constructed of optical rotation members or waveplates, or be the aforementioned wave plates shown in FIGS. 23A to 23C.In FIG. 33B, if the linearly polarized light coming into thepolarization unit 5G is a Y direction linearly polarized light, then thefirst partial light beam F11 does not pass through any of thepolarization rotation members 51G, 52G and 56G, and remains the Ydirection linearly polarized light as it is at a position justdownstream from the polarization unit 5G. The second partial light beamF12 passes through the polarization rotation member 51G, and is a Xdirection linearly polarized light at a position just downstream frompolarization unit 5G. The third partial light beam F13 passes throughthe polarization rotation members 51G and 52G, and is a linearlypolarized light of +225 degree oblique direction at a position justdownstream from the polarization unit 5G. The fourth partial light beamF14 passes through the polarization rotation members 51G, 52G and 56G,and is a linearly polarized light of +315 degree oblique direction at aposition just downstream from the polarization unit 5G. Further, withthe configuration of FIG. 33B, when using only the X direction linearlypolarized light and the Y direction linearly polarized light to carryout illumination, it is possible to insert only the one polarizationrotation member 51G into the illumination optical path.

Further, as shown in FIG. 34, in addition to the configuration of FIG.33B, it is also possible to provide a polarization rotation member 57adapted to rotate the polarization direction of a linearly polarizedincident light by 22.5 degrees+180×n degrees (n is an integer). Further,in FIG. 34, the members having the same functions as those of themembers in the configuration of FIG. 33B are denoted by the referencenumerals same as those of the members in FIG. 33B.

An explanation will be given about aspects, of FIG. 34, which aredifferent from those of FIG. 33B. If the linearly polarized light cominginto the polarization unit 5G is a Y direction linearly polarized light,then a fifth partial light beam F15 passes through the polarizationrotation member 57, and is a linearly polarized light of +22.5 degreeoblique direction at a position just downstream from the polarizationunit 5G. A sixth partial light beam F16 passes through the polarizationrotation members 51G and 57, and is a linearly polarized light of +112.5degree oblique direction at a position just downstream from thepolarization unit 5G. A seventh partial light beam F17 passes throughthe polarization rotation members 51G, 52G and 57, and is a linearlypolarized light of +247.5 degree oblique direction at a position justdownstream from the polarization unit 5G. An eighth partial light beamF18 passes through the polarization rotation members 51G, 52G, 56G and57, and is a linearly polarized light of +337.5 degree oblique directionat a position just downstream from the polarization unit 5G.

In the example of FIG. 34, the polarization rotation member 57 ismovable in a direction (the Y direction) orthogonal to the movingdirection (the X direction) of the polarization rotation members 51G,52G and 56G and, by the moving of the polarization rotation member 57,it is possible to change the ratio of cross-sectional area between thefirst partial light beam F11 and the fifth partial light beam F15, theratio of cross-sectional area between the second partial light beam F12and the sixth partial light beam F16, the ratio of cross-sectional areabetween the third partial light beam F13 and the seventh partial lightbeam F17, and the ratio of cross-sectional area between the fourthpartial light beam F14 and the eighth partial light beam F18. Further,the polarization rotation member 57 may also be moved in the X directionof the figure.

Further, in each of the abovementioned embodiment and modifications, itis also possible to arrange a phase modulation member for reducing theinfluence of the retardation caused due to the optical system arrangedon the illumination objective surface side of the polarization unit inthe illumination optical path on the illumination objective surface sideof the polarization unit. FIG. 35 shows an example of arranging such aphase modulation member 15 in the illumination optical path on theillumination objective surface side of the polarization unit 5, whereinthe members having the same functions as those of the members in theembodiment of FIG. 2 are denoted by the reference numerals same as thoseof the members in FIG. 2.

In FIG. 35, the phase modulation member 15 is a wave plate which extendsacross an entire cross section of the illumination optical path and hasa uniform thickness, and whose optic axis is set along the Y direction(or the X direction). In other words, the optic axis of the wave plateconstructing the phase modulation member 15 is set along a directioncorresponding to the polarization direction of the p-polarized light orthe polarization direction of the s-polarized light with respect to thereflecting surfaces of the flat reflecting mirrors MR2 and MR3 in theoptical system on the illumination objective surface side of thepolarization unit 5.

If the phase modulation member 15 is not provided, then due to theretardation (a phenomenon that phase difference occurs between a pair oflinearly polarized light components whose polarization directions areorthogonal to each other) caused by a succeeding optical system (theoptical system arranged between the polarization unit 5 and the reticleR or the wafer W, especially the flat reflecting mirrors MR2 and MR3)arranged in the optical path on the downstream side from thepolarization unit 5, the linearly polarized light (obliquely polarizedlight), which has a polarization direction not along the plane (the Y-Zplane) including the optical axes upstream and downstream of the flatreflecting mirrors or not along the plane (the X-Z plane) beingorthogonal to that plane (the Y-Z plane) and including the optical axis,is liable to become an elliptically polarized light.

In the example of FIG. 35, the light beam of the longitudinalpolarization (the Y direction linearly polarized light) and thetransverse polarization (the X direction linearly polarized light) fromthe polarization unit 5 is almost not subjected to the phase modulationby the phase modulation member 15, and the light beam from the phasemodulation member 15 nearly maintains its polarization direction. On theother hand, the light beam of oblique polarization from the polarizationunit 5 is subjected to the phase modulation by the phase modulationmember 15, and becomes a light beam of elliptical polarization whichalmost sets off the elliptical polarization of the obliquely polarizedlight due to the abovementioned succeeding optical system. Thepolarization degree of this light beam having elliptical polarizationdepends on the thickness of the wave plate constructing the phasemodulation member 15.

By this configuration, it is possible to reduce the influence of theretardation caused by the succeeding optical system arranged in theoptical path on the downstream side from the polarization unit 5. Thephase modulation member 15 of such a kind is not limited to be arrangedat the position just downstream from the polarization unit 5, but canalso be arranged in any position as long as in the illumination opticalpath on the illumination objective surface side of the polarization unit5. Further, when using only the X direction linearly polarized light andthe Y direction linearly polarized light to carry out the illumination,the phase modulation member may be withdrawn from the illuminationoptical path.

The exposure apparatus of the embodiment described above is produced byassembling the various subsystems including the respective constitutiveelements as recited in claims of this application so that thepredetermined mechanical accuracy, the electrical accuracy, and theoptical accuracy are maintained. In order to secure the variousaccuracies, those performed before and after the assembling include theadjustment for achieving the optical accuracy for the various opticalsystems, the adjustment for achieving the mechanical accuracy for thevarious mechanical systems, and the adjustment for achieving theelectrical accuracy for the various electrical systems. The steps ofassembling the various subsystems into the exposure apparatus include,for example, the mechanical connection, the wiring connection of theelectric circuits, and the piping connection of the air pressurecircuits among the various subsystems. It goes without saying that thesteps of assembling the respective individual subsystems are performedbefore performing the steps of assembling the various subsystems intothe exposure apparatus. When the steps of assembling the varioussubsystems into the exposure apparatus are completed, the overalladjustment is performed to secure the various accuracies of the entireexposure apparatus. It is also appropriate that the exposure apparatusis produced in a clean room in which, for example, the temperature andthe cleanness are managed.

Next, an explanation will be made about a method for producing thedevice by using the exposure apparatus according to the embodimentdescribed above. FIG. 36 shows a flow chart illustrating steps ofproducing a semiconductor device. As shown in FIG. 36, in the steps ofproducing the semiconductor device, a metal film is vapor-deposited onthe wafer W as the substrate for the semiconductor device (Step S40),and the vapor-deposited metal film is coated with a photoresist which isa photosensitive material (Step S42). Subsequently, a pattern formed onthe mask (reticle) M is transferred to respective shot areas on thewafer W by using the projection exposure apparatus of the embodimentdescribed above (Step S44: exposure step). The development of the waferW for which the transfer is completed, i.e., the development of thephotoresist to which the pattern has been transferred is performed (StepS46: development step).

After that, the processing such as the etching or the like is performedfor the surface of the wafer W by using the resist pattern generated onthe surface of the wafer W in Step S46 as a mask (Step S48: processingstep). In this context, the resist pattern is the photoresist layer inwhich protrusions and recesses having the shapes corresponding to thepattern transferred by the projection exposure apparatus of theembodiment described above are generated, wherein the recesses penetratethrough the photoresist layer. In Step S48, the processing is performedfor the surface of the wafer W via the resist pattern. The processing,which is performed in Step S48, includes, for example, at least one ofthe etching of the surface of the wafer W and the film formation of themetal film or the like. In Step S44, the projection exposure apparatusof the embodiment described above performs the transfer of the patternby using the wafer W coated with the photoresist as the photosensitivesubstrate, i.e., a plate P.

FIG. 37 shows a flow chart illustrating steps of producing a liquidcrystal device such as a liquid crystal display element or the like. Asshown in FIG. 37, in the steps of producing the liquid crystal device, apattern forming step (Step S50), a color filter forming step (Step S52),a cell assembling step (Step S54), and a module assembling step (StepS56) are successively performed. In the pattern forming step of StepS50, a predetermined pattern such as a circuit pattern, an electrodepattern or the like is formed on a plate P which is a glass substratecoated with a photoresist by using the projection exposure apparatus ofthe embodiment described above. The pattern forming step includes anexposure step of transferring the pattern to the photoresist layer byusing the projection exposure apparatus of the embodiment describedabove, a development step of performing the development of the plate Pto which the pattern is transferred, i.e., the development of thephotoresist layer on the glass substrate to generate the photoresistlayer having a shape corresponding to the pattern, and a processing stepof processing the surface of the glass substrate via the developedphotoresist layer.

In the color filter forming step of Step S52, a color filter is formed,in which a large number of dot sets each composed of three dotscorresponding to R (Red), G (Green), and B (Blue) are arranged in amatrix form, or a plurality of filter sets each composed of threestripes of R, G, and B are arranged in the horizontal scanningdirection. In the cell assembling step of Step S54, a liquid crystalpanel (liquid crystal cell) is assembled by using the glass substrate onwhich the predetermined pattern is formed in Step S50 and the colorfilter which is formed in Step S52. Specifically, for example, a liquidcrystal panel is formed by injecting the liquid crystal into the spacebetween the glass substrate and the color filter. In the moduleassembling step of Step S56, various parts including, for example, anelectric circuit and a backlight, which are provided to allow the liquidcrystal panel to perform the displaying operation, are attached to theliquid crystal panel which is assembled in Step S54.

The present teaching is not limited to the application to the exposureapparatus for producing the semiconductor device. The present teachingis also widely applicable, for example, to the exposure apparatus forproducing the liquid crystal display device to be formed on therectangular glass plate or the display apparatus such as the plasmadisplay or the like as well as the exposure apparatus for producingvarious devices including, for example, the image pickup device (forexample, CCD), the micromachine, the thin film magnetic head, and theDNA chip. Further, the present teaching is also applicable to theexposure step (exposure apparatus) to be used when the mask (forexample, the photomask and the reticle) formed with the mask pattern forvarious devices is produced by using the photolithography step.

In the embodiment described above, the ArF excimer laser light(wavelength: 193 nm) and the KrF excimer laser light (wavelength: 248nm) are used as the exposure light. However, there is no limitationthereto. The present teaching is also applicable to any otherappropriate laser light source including, for example, the F₂ laserlight source for supplying the laser beam having a wavelength of 157 nm,the pulse laser light source such as the Ar₂ laser (output wavelength:126 nm), the Kr₂ laser (output wavelength: 146 nm) and the like, theg-ray (wavelength: 436 nm), harmonic generator for the YAG laser, andthe ultra-high pressure mercury lamp for generating the emission linesuch as the i-ray (wavelength: 365 nm) or the like.

For example, as disclosed in U.S. Pat. No. 7,023,610, it is alsoappropriate to use the harmonic wave as the vacuum ultraviolet light,the harmonic wave being obtained by amplifying the single wavelengthlaser beam which is in the infrared region or the visible region andwhich is oscillated from the fiber laser or the DFB semiconductor laserwith, for example, a fiber amplifier doped with erbium (or both oferbium and ytterbium) and performing the wavelength conversion toconvert the amplified laser beam into the ultraviolet light by using thenonlinear optical crystal.

In the embodiment described above, it is also appropriate to apply atechnique in which the inside of the optical path defined between theprojection optical system and the photosensitive substrate is filledwith a medium (typically a liquid) having a refractive index larger than1.1, i.e., the so-called liquid immersion method. In this case, thoseadoptable as the technique for filling the inside of the optical pathdefined between the projection optical system and the photosensitivesubstrate with the liquid include, for example, a technique in which theoptical path is locally filled with the liquid such as the techniquedisclosed in International Publication No. WO99/49504, a technique inwhich a stage which holds a substrate as an exposure objective is movedin a liquid bath such as the technique disclosed in Japanese PatentApplication Laid-open No. 6-124873, and a technique in which a liquidpool having a predetermined depth is formed on a stage and a substrateis held therein such as the technique disclosed in Japanese PatentApplication Laid-open No. 10-303114. Here, the teachings of the pamphletof International Patent Publication No. WO99/49504, Japanese PatentApplication Laid-open No. 6-124873 and Japanese Patent ApplicationLaid-open No. 10-303114 are incorporated herein by reference.

In the embodiment described above, the projection optical system of theexposure apparatus is not limited to the reduction system, which may beany one of the 1× magnification system and the enlarging (magnifying)system. The projection optical system is not limited to the refractivesystem, which may be any one of the reflection system and thecata-dioptric system. The projected image may be any one of the invertedimage and the erected image.

For example, as disclosed in International Publication No. 2001/035168,the present teaching is applicable to an exposure apparatus (lithographysystem) in which a line-and-space pattern is formed on a wafer W byforming interference fringes on the wafer W.

Further, for example, as disclosed in U.S. Pat. No. 6,611,316, thepresent teaching is applicable to an exposure apparatus in which tworeticle patterns are combined (synthesized) on a wafer via a projectionoptical system, and one shot area on the wafer is subjected to thedouble exposure substantially simultaneously by means of one time of thescanning exposure.

In the embodiment described above, the object on which the pattern is tobe formed (object as the exposure objective to be irradiated with theenergy beam), is not limited to the wafer. The object may be any otherobject including, for example, glass plates, ceramic substrates, filmmembers, and mask blanks.

In the embodiment described above, the present teaching is applied tothe illumination optical system for illuminating the mask (or the wafer)in the exposure apparatus. However, there is no limitation thereto. Thepresent teaching is also applicable to any general illumination opticalsystem for illuminating any illumination objective surface other thanthe mask (or the wafer).

While the particular aspects of embodiment(s) of the ILLUMINATIONOPTICAL SYSTEM, EXPOSURE APPARATUS, DEVICE PRODUCTION METHOD, AND LIGHTPOLARIZATION UNIT described and illustrated in this patent applicationin the detail required to satisfy 35 U.S.C. § 112 is fully capable ofattaining any above-described purposes for, problems to be solved by orany other reasons for or objects of the aspects of an embodiment(s)above described, it is to be understood by those skilled in the art thatit is the presently described aspects of the described embodiment(s) ofthe subject matter claimed are merely exemplary, illustrative andrepresentative of the subject matter which is broadly contemplated bythe claimed subject matter. The scope of the presently described andclaimed aspects of embodiments fully encompasses other embodiments whichmay now be or may become obvious to those skilled in the art based onthe teachings of the Specification. The scope of the presentILLUMINATION OPTICAL SYSTEM, EXPOSURE APPARATUS, DEVICE PRODUCTIONMETHOD, AND LIGHT POLARIZATION UNIT is solely and completely limited byonly the appended claims and nothing beyond the recitations of theappended claims. Reference to an element in such claims in the singularis not intended to mean nor shall it mean in interpreting such claimelement “one and only one” unless explicitly so stated, but rather “oneor more”. All structural and functional equivalents to any of theelements of the above-described aspects of an embodiment(s) that areknown or later come to be known to those of ordinary skill in the artare expressly incorporated herein by reference and are intended to beencompassed by the present claims. Any term used in the Specificationand/or in the claims and expressly given a meaning in the Specificationand/or claims in the present application shall have that meaning,regardless of any dictionary or other commonly used meaning for such aterm. It is not intended or necessary for a device or method discussedin the Specification as any aspect of an embodiment to address each andevery problem sought to be solved by the aspects of embodimentsdisclosed in this application, for it to be encompassed by the presentclaims. No element, component, or method step in the present disclosureis intended to be dedicated to the public regardless of whether theelement, component, or method step is explicitly recited in the claims.No claim element in the appended claims is to be construed under theprovisions of 35 U.S.C. § 112, sixth paragraph, unless the element isexpressly recited using the phrase “means for” or, in the case of amethod claim, the element is recited as a “step” instead of an “act.”

It will be understood also by those skilled in the art that, infulfillment of the patent statutes of the United States, Applicant(s)has disclosed at least one enabling and working embodiment of eachinvention recited in any respective claim appended to the Specificationin the present application and perhaps in some cases only one.Applicant(s) has used from time to time or throughout the presentapplication definitive verbs (e.g., “is”, “are”, “does”, “has”,“includes” or the like) and/or other definitive verbs (e.g., “produces,”“causes” “samples,” “reads,” “signals” or the like) and/or gerunds(e.g., “producing,” “using,” “taking,” “keeping,” “making,”“determining,” “measuring,” “calculating” or the like), in defining anaspect/feature/element of, an action of or functionality of, and/ordescribing any other definition of an aspect/feature/element of anembodiment of the subject matter being disclosed. Wherever any suchdefinitive word or phrase or the like is used to describe anaspect/feature/element of any of the one or more embodiments disclosedherein, i.e., any feature, element, system, sub-system, process oralgorithm step, particular material, or the like, it should be read, forpurposes of interpreting the scope of the subject matter of whatapplicant(s) has invented, and claimed, to be preceded by one or more,or all, of the following limiting phrases, “by way of example,” “forexample,” “as an example,” “illustratively only,” “by way ofillustration only,” etc., and/or to include any one or more, or all, ofthe phrases “may be,” “can be”, “might be,” “could be” and the like. Allsuch features, elements, steps, materials and the like should beconsidered to be described only as a possible aspect of the one or moredisclosed embodiments and not as the sole possible implementation of anyone or more aspects/features/elements of any embodiments and/or the solepossible embodiment of the subject matter of what is claimed, even if,in fulfillment of the requirements of the patent statutes, Applicant(s)has disclosed only a single enabling example of any suchaspect/feature/element of an embodiment or of any embodiment of thesubject matter of what is claimed. Unless expressly and specifically sostated in the present application or the prosecution of thisapplication, that Applicant(s) believes that a particularaspect/feature/element of any disclosed embodiment or any particulardisclosed embodiment of the subject matter of what is claimed, amountsto the one and only way to implement the subject matter of what isclaimed or any aspect/feature/element recited in any such claim,Applicant(s) does not intend that any description of any disclosedaspect/feature/element of any disclosed embodiment of the subject matterof what is claimed in the present patent application or the entireembodiment shall be interpreted to be such one and only way to implementthe subject matter of what is claimed or any aspect/feature/elementthereof, and to thus limit any claim which is broad enough to cover anysuch disclosed implementation along with other possible implementationsof the subject matter of what is claimed, to such disclosedaspect/feature/element of such disclosed embodiment or such disclosedembodiment. Applicant(s) specifically, expressly and unequivocallyintends that any claim that has depending from it a dependent claim withany further detail of any aspect/feature/element, step, or the like ofthe subject matter of what is claimed recited in the parent claim orclaims from which it directly or indirectly depends, shall beinterpreted to mean that the recitation in the parent claim(s) was broadenough to cover the further detail in the dependent claim along withother implementations and that the further detail was not the only wayto implement the aspect/feature/element claimed in any such parentclaim(s), and thus be limited to the further detail of any suchaspect/feature/element recited in any such dependent claim to in any waylimit the scope of the broader aspect/feature/element of any such parentclaim, including by incorporating the further detail of the dependentclaim into the parent claim.

Further, the present application may also set forth claims as follows:

1. An illumination optical system which illuminates an illuminationobjective surface with a light from a light source, the illuminationoptical system comprising:

a spatial light modulator which has a plurality of optical elementsarranged within a predetermined plane and controlled individually, andwhich forms a light intensity distribution in an illumination pupil ofthe illumination optical system in a variable manner; and

a polarization unit which is arranged in a conjugate position opticallyconjugate with the predetermined plane in an optical path of theillumination optical system, and which changes a polarization state of apart of an incident light beam, and then emits the incident light beamas an outgoing light beam.

2. The illumination optical system according to claim 1, wherein thepolarization unit is arranged in the conjugate position in the opticalpath on the illumination objective surface side with respect to thespatial light modulator.

3. The illumination optical system according to claim 1 or 2, whereinthe incident light beam includes a first partial light beam and a secondpartial light beam different from the first partial light beam; and thepolarization unit has a first optical element which changes thepolarization state of the second partial light beam in the incidentlight beam without exerting any effect on the first partial light beamin the incident light beam.

4. The illumination optical system according to claim 3, wherein thefirst optical element is arranged on a first plane along a cross sectionof the incident light beam, and configured to be movable along the firstplane for changing the ratio between the cross-sectional area of thefirst partial light beam via the first plane and the cross-sectionalarea of the second partial light beam via the first plane.

5. The illumination optical system according to claim 3 or 4, whereinthe first optical element has a pair of edges extending in a firstdirection parallel to one pair of sides of a rectangular cross sectionof the incident light beam, and is movable in a second directionorthogonal to the first direction.

6. The illumination optical system according to claim 3 or 4, whereinthe first optical element has a first edge extending in a thirddirection obliquely intersecting one pair of sides of a rectangularcross section of the incident light beam, and a second edge extending ina fourth direction different from the third direction, and is movabletwo-dimensionally along the cross section of the incident light beam.

7. The illumination optical system according to claim 6, wherein thefourth direction in which the second edge of the first optical elementextends is a direction obliquely intersecting the one pair of sides.

8. The illumination optical system according to any one of claims 3 to7, wherein the polarization unit has a second optical element whichchanges a polarization state of a third partial light beam which is atleast part of the second partial light beam via the first opticalelement, and a polarization state of a fourth partial light beam whichis at least part of the first partial light beam coming into the secondoptical element without passing through the first optical element.

9. The illumination optical system according to claim 8, wherein thesecond optical element is arranged on a second plane along the crosssection of the incident light beam, and configured to be movable alongthe second plane for changing a ratio between a cross-sectional area ofthe third partial light beam via the second plane and a cross-sectionalarea of the fourth partial light beam via the second plane.

10. The illumination optical system according to claim 8 or 9, whereinthe second optical element has a pair of edges extending in a firstdirection parallel to one pair of sides of a rectangular cross sectionof the incident light beam, and is movable in a second directionorthogonal to the first direction.

11. The illumination optical system according to claim 8 or 9, whereinthe second optical element has a third edge extending in a fifthdirection obliquely intersecting one pair of sides of a rectangularcross section of the incident light beam, and a fourth edge extending ina sixth direction different from the fifth direction, and is movabletwo-dimensionally along the cross section of the incident light beam.

12. The illumination optical system according to claim 11, wherein thesixth direction in which the fourth edge of the second optical elementextends is a direction obliquely intersecting the one pair of sides.

13. The illumination optical system according to any one of claims 3 to12, wherein the first optical element has an optical rotation memberformed of an optical material having optical rotation property.

14. The illumination optical system according to any one of claims 8 to13, wherein at least one of the first optical element and the secondoptical element includes an optical rotation member formed of an opticalmaterial having optical rotation property.

15. The illumination optical system according to claim 13 or 14, whereinthe optical rotation member comprises a first optical rotation memberformed of a clockwise optical rotation material, and a second opticalrotation member formed of a counterclockwise optical rotation materialand arranged adjacent to the first optical rotation member.

16. The illumination optical system according to claim 14 or 15, whereina phase difference imparting member which imparts the incident lightbeam with phase differences which are different based on an incidentposition of the incident light beam is arranged on an optical Fouriertransform plane of the predetermined plane.

17. The illumination optical system according to any one of claims 3 to16, wherein the first optical element includes a wave plate whichchanges the incident light beam into a light in a predeterminedpolarization state.

18. The illumination optical system according to any one of claims 8 to17, wherein at least one of the first optical element and the secondoptical element includes a wave plate which changes the incident lightbeam into a light in a predetermined polarization state.

19. The illumination optical system according to claim 17 or 18, whereinthe wave plate is rotatable along a cross section of the incident lightbeam.

20. The illumination optical system according to claim 18 or 19, whereinthe wave plate comprises a first wave plate having an optic axis along afirst direction within a plane along the cross section of the incidentlight beam, and a second wave plate having an optic axis along a seconddirection different from the first direction within the plane along thecross section of the incident light beam.

21. The illumination optical system according to any one of claims 8 to20, wherein at least one of the first optical element and the secondoptical element includes a polarizer which selects a light in apredetermined polarization state from the incident light beam and thenemits the selected light.

22. The illumination optical system according to any one of claims 8 to21, wherein the first optical element and the second optical element arearranged adjacent to each other.

23. The illumination optical system according to any one of claims 1 to22, further comprising a relay optical system arranged between thepredetermined plane and a position conjugate with the predeterminedplane.

24. The illumination optical system according to claim 23, wherein thefirst optical element and the second optical element are arranged acrossthe position optically conjugate with the predetermined plane.

25. The illumination optical system according to claim 23 or 24, whereinthe position optically conjugate with the predetermined plane is aposition on an optical axis of the relay optical system.

26. The illumination optical system according to any one of claims 23 to25, wherein the predetermined plane on which the plurality of opticalelements of the spatial light modulator are arranged is inclined withrespect to a plane orthogonal to an optical axis of the relay opticalsystem; and the first optical element is configured to be movable in adirection along a plane optically conjugate with the predetermined planewith respect to the relay optical system.

27. The illumination optical system according to any one of claims 8 to21, further comprising a second relay optical system which is arrangedbetween the first optical element and the second optical element, andwhich sets the first optical element and the second optical elementoptically conjugate with each other.

28. The illumination optical system according to any one of claims 1 to27, wherein the polarization unit has a depolarizing element insertableto and removable from the illumination optical path.

29. The illumination optical system according to claim 28, wherein thedepolarizing element is insertable and removable at a position opticallyconjugate with the predetermined plane in the illumination optical path,or in the vicinity of the position optically conjugate with thepredetermined plane.

30. The illumination optical system according to any one of claims 1 to29, further comprising an optical integrator, wherein the polarizationunit is arranged in an optical path between the spatial light modulatorand the optical integrator.

31. The illumination optical system according to any one of claims 1 to30, wherein the spatial light modulator includes a plurality of mirrorelements arranged two-dimensionally within the predetermined plane, anda drive portion which controls and drives attitudes of the plurality ofmirror elements individually.

32. The illumination optical system according to claim 31, wherein thedrive portion changes orientations of the plurality of mirror elementscontinuously or discretely.

33. The illumination optical system according to claim 31 or 32, whereinin a case that a group of mirror elements positioned in a first regionon the predetermined plane, among the plurality of mirror elements, isdefined as a first mirror element group, and that a group of mirrorelements positioned in a second region different from the first regionon the predetermined plane, among the plurality of mirror elements, isdefined as a second mirror element group, the drive portion controls anddrives the first mirror element group such that a light via the firstmirror element group is guided to a first pupil region on an opticalFourier transform plane of the predetermined plane, and controls anddrives the second mirror element group such that a light via the secondmirror element group is guided to a second pupil region on the opticalFourier transform plane of the predetermined plane.

34. The illumination optical system according to claim 33, wherein thefirst pupil region is different from the second pupil region.

35. The illumination optical system according to claim 33 or 34, whereinthe first pupil region partially overlaps the second pupil region.

36. The illumination optical system according to any one of claims 33 to35, wherein the polarization unit includes a first optical element whichchanges a polarization state of the second partial light beam via thesecond mirror element group without exerting any effect on the firstpartial light beam via the first mirror element group.

37. The illumination optical system according to any one of claims 1 to36, wherein the polarization unit is arranged in the conjugate positionin the optical path on the light source side with respect to the spatiallight modulator.

38. The illumination optical system according to claim 37, furthercomprising an illuminance uniformization optical system which isarranged in the optical path on the light source side with respect tothe conjugate position, and improves an illuminance uniformity within aplane including the conjugate position to be higher than an illuminanceuniformity within a cross section of the incident light beam.

39. The illumination optical system according to claim 37, furthercomprising a wavefront division optical system arranged in the opticalpath on the light source side with respect to the conjugate position andwhich performs wavefront division of the incident light beam andsuperimposes the divided light beam on a plane including the conjugateposition.

40. The illumination optical system according to any one of claims 1 to39, wherein the illumination optical system is used in combination witha projection optical system which forms a plane optically conjugate withthe illumination objective surface, the illumination pupil is defined ata position optically conjugate with an aperture stop of the projectionoptical system.

41. An exposure apparatus comprising the illumination optical system asdefined in any one of claims 1 to 40 for illuminating a predeterminedpattern, the exposure apparatus exposing a photosensitive substrate withthe predetermined pattern.

42. The exposure apparatus according to claim 41, further comprising aprojection optical system which forms an image of the predeterminedpattern on the photosensitive substrate.

43. A device production method comprising the steps of:

exposing the photosensitive substrate with the predetermined pattern byusing the exposure apparatus as defined in claim 41 or 42;

developing the photosensitive substrate to which the predeterminedpattern is transferred and forming a mask layer having a shapecorresponding to the predetermined pattern on a surface of thephotosensitive substrate; and

processing the surface of the photosensitive substrate via the masklayer.

44. A polarization unit which changes a polarization state of a part ofan incident light beam having a rectangular cross section and then emitsthe incident light beam as an outgoing light beam, the polarization unitcomprising:

a first optical element which is arranged on a first plane along thecross section of the incident light beam and which changes apolarization state of a second partial light beam in the incident lightbeam, without exerting any effect on a first partial light beam in theincident light beam; and

a second optical element which is arranged on a second plane along thecross section of the incident light beam and which changes apolarization state of a third partial light beam which is at least apart of the second partial light beam passed through the first opticalelement, and a polarization state of a fourth partial light beam whichis at least a part of the first partial light beam which coming into thesecond optical element without passing through the first opticalelement,

wherein the first optical element has a first edge extending in a thirddirection obliquely intersecting one pair of sides of the rectangularcross section of the incident light beam, and a second edge extending ina fourth direction different from the third direction.

45. The polarization unit according to claim 44, wherein at least one ofthe first optical element and the second optical element is configuredto be movable along the first plane or the second plane for changing aratio between a cross-sectional area of the first partial light beam, across-sectional area of the second partial light beam, a cross-sectionalarea of the third partial light beam, and a cross-sectional area of thefourth partial light beam.

46. The polarization unit according to claim 44 or 45, wherein thefourth direction in which the second edge of the first optical elementextends is a direction obliquely intersecting the one pair of sides.

47. The polarization unit according to any one of claims 44 to 46,wherein the second optical element has a third edge extending in a fifthdirection obliquely intersecting one pair of sides of the rectangularcross section of the incident light beam, and a fourth edge extending ina sixth direction different from the fifth direction; and the secondoptical element is movable two-dimensionally along the second plane.

48. The polarization unit according to any one of claims 44 to 47,wherein at least one of the first optical element and the second opticalelement includes an optical rotation member formed of an opticalmaterial having optical rotation property.

49. The polarization unit according to any one of claims 44 to 48,wherein at least one of the first optical element and the second opticalelement includes a wave plate which changes the incident light beam intoa light having a predetermined polarization state.

50. The polarization unit according to claim 49, wherein the wave plateis rotatable along the cross section of the incident light beam.

51. The polarization unit according to any one of claims 44 to 50,wherein at least one of the first optical element and the second opticalelement has a polarizer which selects a light in a predeterminedpolarization state from the incident light beam and emits the selectedlight.

The invention claimed is:
 1. An illumination optical system whichilluminates an object with an illumination light, the illuminationoptical system comprising: a fly's-eye lens having a back focal planearranged on a pupil plane of the illumination optical system or in avicinity of the pupil plane, the pupil plane being in a substantiallyoptical Fourier transform relation with a predetermined plane on whichthe object is to be arranged; a spatial light modulator which isarranged on an incident side of the fly's-eye lens and which includes aplurality of mirror elements; and a polarization unit including aplurality of optical elements each of which is capable of being arrangedin an optical path of the illumination light and each of which changes apolarization state of the illumination light, wherein the spatial lightmodulator is capable of changing an intensity distribution, of theillumination light, on the pupil plane, and is capable of forming theintensity distribution, on the pupil plane, in which at least a part ofthe illumination light is distributed to an off-axis region deviatedfrom an optical axis of the illumination optical system, a first opticalelement among the plurality of optical elements of the polarization unittransforms a polarization state of the illumination light coming intothe first optical element with the polarization state in which alinearly polarized light having a polarization direction in apredetermined one direction is a main component such that the at least apart of the illumination light, in the off-axis region, is linearlypolarized light having a polarizing direction in a circumferentialdirection around the optical axis, to make the at least the part of theillumination light illuminated on the object via the off-axis regionhave a polarization state in which s-polarized light is a maincomponent, an oblique light, included in the illumination light, whichcomes into the first optical element obliquely to the optical axis isimparted a polarization state different from a linear polarizationhaving a polarizing direction in the circumferential direction via thefirst optical element and is distributed to the off-axis region, and avertical light, included in the illumination light, which comes into thefirst optical element substantially vertically is imparted the linearpolarization having the polarizing direction in the circumferentialdirection via the first optical element and is distributed to theoff-axis region, the polarization unit includes a correction opticalelement which transforms the oblique light such that the oblique lighton the pupil plane is the linearly polarized light having the polarizingdirection in the circumferential direction, the correction opticalelement being different from the first optical element.
 2. Theillumination optical system according to claim 1, wherein the correctionoptical element is arranged adjacent to the first optical element on anexit side of the first optical element.
 3. The illumination opticalsystem according to claim 1, wherein the correction optical elementincludes a phase difference imparting member which imparts a phasedifference to the illumination light.
 4. The illumination optical systemaccording to claim 3, wherein the phase difference imparting member isarranged such that the phase difference imparting member and the firstoptical element have substantially optical Fourier transform relation.5. The illumination optical system according to claim 1, wherein atleast a part of the polarization unit is arranged on an incident side ofthe spatial light modulator.
 6. The illumination optical systemaccording to claim 1, wherein at least a part of the polarization unitis arranged in an optical path between the spatial light modulator andthe fly's-eye lens.
 7. The illumination optical system according toclaim 1, wherein the polarization unit is arranged in the optical pathsuch that the first optical element and a second optical element arepartially overlapped with respect to a direction orthogonal to theoptical axis, the second optical element being included in the pluralityof optical elements of the polarization unit and being different fromthe first optical element, and the spatial light modulator is drivensuch that a first light included in the illumination light isdistributed to a first region in the off-axis region through both of thefirst and second elements, a second light included in the illuminationlight is distributed to a second region in the off-axis region throughone of the first and second optical elements, the second light and thesecond region being different from the first light and the first regionrespectively.
 8. The illumination optical system according to claim 7,wherein each of the first optical element and the second optical elementis arranged at a conjugate position conjugate with the pupil plane or inthe vicinity of the conjugate position.
 9. The illumination opticalsystem according to claim 8, wherein the first and second opticalelements are arranged at positions different from each other withrespect to a direction parallel to the optical axis.
 10. Theillumination optical system according to claim 9, wherein the first andsecond optical elements are arranged adjacent to each other.
 11. Theillumination optical system according to claim 7, wherein each of thefirst and second optical elements is arranged substantially conjugatewith an arrangement plane on which the plurality of mirror elements ofthe spatial light modulator are arranged.
 12. The illumination opticalsystem according to claim 11, wherein the spatial light modulator isarranged such that the arrangement plane and the pupil plane havesubstantially optical Fourier transform relation.
 13. The illuminationoptical system according to claim 7, wherein each of the first andsecond optical elements is made of an optical material having an opticalactivity, and is arranged such that optic axes of the first and secondoptical elements are substantially identical to the optical axis. 14.The illumination optical system according to claim 13, wherein the firstand second optical elements have thicknesses, with respect to adirection parallel to the optical axis, different from each other. 15.The illumination optical system according to claim 7, wherein each ofthe first and second optical elements is a wave plate, and the first andsecond optical elements are arranged such that optic axes of the firstand second optical elements are substantially orthogonal to the opticalaxis.
 16. The illumination optical system according to claim 7, whereinthe spatial light modulator is driven such that a third light includedin the illumination light is distributed to a third region in theoff-axis region through the other of the first and second opticalelements, the third light being different from the first and secondlights and the third region being different from the first and secondregions.
 17. The illumination optical system according to claim 16,wherein the first and second optical elements have polarizationtransformation properties different from each other such that adirection of the linear polarization of the second light on the pupilplane and a direction of the linear polarization of the third light onthe pupil plane are different from each other.
 18. The illuminationoptical system according to claim 16, wherein the spatial lightmodulator is driven such that a fourth light included in theillumination light is distributed to a fourth region in the off-axisregion bypassing both of the first and second optical elements, thefourth light being different from the first, second and third lights andthe fourth region being different from the first, second and thirdregions.
 19. The illumination optical system according to claim 18,wherein polarization states of the first, second, third and fourthlights are transformed such that directions of the linear polarizationof the first, second, third and fourth lights on the pupil plane aredifferent from each other.
 20. The illumination optical system accordingto claim 19, further comprising a uniformization element which isarranged on an incident side of the spatial light modulator and whichrealizes a substantially uniform intensity distribution of theillumination light on the spatial light modulator.
 21. The illuminationoptical system according to claim 20, further comprising at least onemirror which is arranged between the fly's eye lens and the first andsecond optical elements of the polarization unit, wherein at least apart of the illumination light distributed to the off-axis regionincludes a light which is imparted a polarization state different fromthe linear polarization having the polarizing direction in thecircumferential direction by the at least one mirror, and thepolarization unit includes a phase modulation member which modulates aphase of at least a part of the illumination light such that the lighton the pupil plane is a linearly polarized light of which polarizationdirection is the circumferential direction.
 22. An exposure apparatuswhich exposes a substrate with an illumination light, the exposureapparatus comprising: the illumination optical system as defined inclaim 1 that illuminates a mask with the illumination light; and aprojection optical system which forms a pattern image of the mask ontothe substrate, wherein a pupil plane of the illumination optical systemand a pupil plane of the projection optical system are arrangedsubstantially conjugate with each other.
 23. A device manufacture methodcomprising: exposing a substrate by using the exposure apparatus asdefined in claim 22; and developing the exposed substrate.
 24. Amanufacture method of an exposure apparatus for exposing a substratewith an illumination light, the manufacture method comprising: providingthe illumination optical system as defined in claim 1 that illuminates amask with the illumination light; and providing a projection opticalsystem which forms a pattern image of the mask onto the substrate,wherein a pupil plane of the illumination optical system and a pupilplane of the projection optical system are arranged substantiallyconjugate with each other.